Optimisation of PID control algorithms for lithography wafer stage

This paper focuses on providing an optimization scheme for the large synchronization errors between multiple motors generated by the PID control algorithm model of the lithography wafer stage under strong external disturbances. First, analyze the motion characteristics of the wafer stage during the scanning exposure stage, designing smooth motion trajectory curve based on 7-segment S-curve. The motion trajectory curves are generated by MATLAB and used as input signals to the control system. Simulation model of lithography wafer stage PID control system is established in SIMULINK according to the characteristics of permanent magnet linear synchronous motor and stage system index requirements. Synchronous control between multiple motors using parallel synchronous control, at this time, the synchronization error is large, and the stage will generate a large torque. On this basis, the cross-coupling structure is designed to optimize the control system model to reduce synchronization errors. The simulation results show that 7-segment S-curve trajectory planning output displacement curve smooth, no acceleration shock in line with the requirements of the wafer stage exposure scanning; The synchronization error between motors reaches 1.682mm when parallel control strategy is used, the synchronization error between motors is reduced to 0.1871mm by cross-coupling structure optimization, the synchronization error is effectively reduced and the feasibility of the optimization scheme is verified.