Adaptive extensions to a multibranch run‐to‐run controller for plasma etching

Fuzzy logic and database learning mechanisms have been incorporated into a generic plasma etching run‐to‐run controller, resulting in a very dynamic, adaptable, and robust system. The system features an Applied 8300 reactive ion etcher controlled by a Techware II equipment controller. A TCP/IP connection links this equipment controller to the run‐to‐run controller residing on a SUN. The run‐to‐run control environment is generic in that the basic control framework and controller development results are applicable to very large scale integrated manufacturing in general. The controller is multibranch as it utilizes multiple algorithms in complementary fashion to achieve process optimization and control. The current implementation utilizes three branches: (1) a linear approximation control algorithm, (2) an optimization algorithm that utilizes (real‐time) data collected in situ to determine optimal run‐to‐run process parameter settings, and (3) a statistical optimization algorithm that utilizes run‐to‐run dat...