Normalized in-line stepper coordinator design by the sequence diagram and production rules: a case study

Generic equipment control, which allows control of multiple types of equipment simultaneously, is made possible under the premise that individual equipment operational scenario can be normalized. Scenario normalization for In-Line Steppers (ILS) in a photolithographic cell is complicated due to the necessity of integrating the track and stepper. To the best of our knowledge, scenario normalization for ILS and has not been addressed before in the literature. To establish the foundation of photolithographic cell control, this paper addresses the scenario normalization procedure for ILS and its implementation. To do so, we use the sequence diagram that highlights the operation details at the equipment level to model the operational scenarios of the stepper and track. Then, the overall operational scenarios are checked against the normalized operational flow to derive normalization rules, expressed in terms of "triggering rules" before being implemented in an event triggering programming platform as a coordinator between the equipment control system and the ILS. The design of an ILS coordinator for a real-world photolithographic cell controller is presented in detail.