The Set-Valued Run-to-Run Controller with Ellipsoid Approximation

In order to successfully apply Run-to-Run (RtR) control or real time control in a semiconductor process, it is very important to estimate the process model. Traditional semiconductor process control methods neglect the importance of robustness due to the estimation methods they use. A new approach, namely the set-valued RtR controller with ellipsoid approximation, is proposed to estimate the process model from a completely different point of view. Because the set-valued RtR controller identifies the process model in the feasible parameter set which is insensitive to noises, the controller is robust to the environment noises. Ellipsoid approximation can significantly reduce the computation load for the set-valued method. In this paper, the Modified Optimal Volume Ellipsoid (MOVE) algorithm is used to estimate the process model in each run. Design of the corresponding controller and parameter selection of the controller are introduced. Simulation results showed that the controller is robust to environment noises and model errors. ∗Phone: 301-405-6578, Fax: 301-314-9281, Email: [email protected] †This work was supported by the Center for Satellite and Hybrid Communication Networks, under NASA cooperative agreement NCC3-528