Supervisory control of a rapid thermal multiprocessor

Abstract

An application of supervisory control theory to a piece of semiconductor manufacturing equipment is presented. The approach allows the flexible design and reliable update of processing recipes to accommodate frequently changing manufacturing requirements. An input-output interpretation of supervisory control theory is given. This interpretation leads to a generic implementation scheme for manufacturing systems. A synthesis fixpoint algorithm implementation using binary decision diagrams enables the design of supervisors of realistic size. A sample synthesis for an oxide growth recipe is performed on a state space of the order of 10/sup 6/ states. The actual implementation of the logic sequencing control software for the application under investigation is described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>