光刻机工件台宏微电机的非线性复合控制

Nonlinear complex controller for macro and micro movement of motors in the wafer stage

针对光刻机工件台长行程直线电机宏动和平面电机高精密微动的耦合运动特点,提出一种宏动跟踪微动的变增益非线性复合控制方法,实现系统高动态纳米级精度的跟踪定位。宏动长行程直线电机采用零相位跟踪前馈控制和双环控制,实现系统无静差跟踪加速度指令;利用扩张状态观测器观测宏动系统的动态变化,补偿系统中的耦合推力和其他扰动;微动平面电机采用变增益非线性控制,根据系统误差幅值的大小,动态的改变控制器增益,以大增益抑制系统加减速时的低频大幅值误差,以小增益避免系统匀速运动时高频噪声的引入。实现系统稳定时间小于30 ms,跟踪误差小于20 nm的跟踪,实验结果表明:该方法可改善系统的动态性能和抗干扰能力,减小系统稳定时间,提高系统的跟踪精度。

For high-speed positioning with nm-level precision is required by using macro movement of long stroke linear motor and high-precision micro movement of planar motor in the wafer stage of lithography, a variable-gain nonlinear complex controller is proposed, in which the macro-motion tracks the micro-motion. The macro movement long stroke linear motor uses a double-loop direct velocity feed forward controller to eliminate static error when tracking acceleration. An extended state observer （ESO） observes the dynamic changes and compensates for cou- pling thrust and other disturbances in the macro system. The micro movement planar motor uses a variable-gain nonlinear controller, which changes the gain of the controller dynamically depending on the error magnitude. Using this method the gain of the controller is adjusted dynamically according to the magnitude of the system error. So that low frequency error is reduced by a large gain as the system accelerates or decelerates, and high frequency noise is rejected by a small gain as the system moves at constant speed. The experiment results show that system dynamic performance and disturbance resistance is improved, stabilizing time is reduced, and tracking precision is enhanced. The system settling time is less than 30ms with tracking error under 20nm.