Modeling complex processability constraints in high-mix semiconductor manufacturing

In semiconductor high-mix fabs, several technology nodes are run on the same line, using tool types from different generations. In this context, processability is a function defining which products can be processed on a given machine considering the current status of both the product and the machine. So in a high-mix context, having an information system that provides reliable information on processability and that can support the evolution of processability rules is fundamental. In this paper, we analyze the key elements for such a system. Based on the example of the implementation of fab constraints at STMicroelectronics' Crolles300 production unit, we illustrate the consequences of the integration of new processability rules and propose flexible and agile UML class diagrams enabling information system to meet evolution requirements. The approach is validated on real fab data, and its impact is discussed.