Adaptive Sliding Mode Control for Magnetic Suspension Short-Stroke Stage in a Reticle Stage

摘要

The reticle stage in lithographic equipment used to manufacture integrated circuits operates at nanometer accuracy during a scanning process. The modeling errors and external disturbances cause the coupling between multiple degrees of freedom (DOF) of the magnetic suspension short-stroke stage in a reticle stage and as a result, the convergence of the tracking errors cannot be guaranteed. In order to improve the servo performance of the short-stroke stage, this paper presents an adaptive sliding mode control (ASMC) method. The structure of short-stroke stage is introduced, and its dynamic model is established. Based on the established dynamic model, an ASMC is designed. Meanwhile, its convergence and stability are proved by Lyapunov stability theory. The experimental results confirm the effectiveness of the proposed control method compared with the linear feedback control method.