Design of Coarse-Fine Combined Synchronization Control System for Lithography Based on Cross-Coupled Sliding Mode Control
In order to achieve high position precision and synchronization between the wafer stage and the reticle stage, a cross-coupled sliding mode control scheme for a coarse-fine combined synchronization servo system of lithography is proposed. To accomplish high bandwidth and high tracking precision, a conventional linear motor is combined with a voice coil motor as a coarse-fine dual-stage control system. A cross-coupled structure is presented to decrease the synchronization error during scanning operation. Sliding mode control law is designed based on the control error and the synchronization error. Simulation results show that the synchronization error and the control error have the same order of magnitude, and the dynamic performance of the control system satisfies the design requirement.
Z. P. Wu and X. L. Chen, "Design of Coarse-Fine Combined Synchronization Control System for Lithography Based on Cross-Coupled Sliding Mode Control", Advanced Materials Research, Vols. 383-390, pp. 2126-2131, 2012