Research on the control of reticle stage macro movement motor

The reticle stage of lithography is a high precision servo motion platform, which requires using macro movement of linear motor and micro movement of voice coil motor to realize an nm-level positioning precision and tracking. In order to increase the control effect and response speed of macro movement motor of reticle stage of lithography, there we present a control strategy in combination with feed-forward thrust fluctuation compensation based on query table, the PID controller, and robust ILC controller. Firstly, the method separate the tracking error that is caused by the motor thrust fluctuation, then according to the speed build a query table to construct feedforward thrust fluctuation model, which is used for system thrust fluctuation compensation; the PID controller aim to improve the anti-interference ability of the system; through adding the attenuation factor, the robust ILC controller ensure the tracking error would be astringe to zero. The results showed that this method can well restrain the effects of thrust fluctuation from the motor, and the macro movement motor positioning quickly and accurately.