双工件台光刻机换台过程的轨迹规划及控制

Trajectory planning and control method for wafer stage exchange process of dual-stage lithography

摘要:

为减小双工件台光刻机的换台时间,提出了一种改进5阶S轨迹和时间-冲击最小控制算法．分析了双驱双桥换台策略,曝光位和预对准位的两个工件台依次执行5个点对点运动完成换台过程．在常规数值积分S轨迹设计方法中,增加了减小冲击的优化项,设计了改进5阶S轨迹使加速度曲线更加平滑．以换台过程的时间-冲击最小为优化指标,为工件台系统设计了最优控制算法从而大幅度减小换台时间,并且克服了单纯以时间最优Bang-Bang控制中加速度突变的缺点．仿真和实验结果表明,利用轨迹规划和最优控制方法可以实现快速换台运动,改进5阶S轨迹加速度曲线最平滑,时间-冲击最优控制比5阶S轨迹具有更短的换台时间．

Abstract:

To reduce the exchange time of dual-stage lithography, a modified fifth-order S-curve planning method and a minimum-time and minimum-jerk control method are proposed. The dual-driver and dual-bridge exchange method of the wafer stages is analyzed, and the wafer stages on the exposure position and pre-alignment position make five point-to-point movements to complete the exchange process. A minimum-jerk optimization index is added to fifth-order S-curve based on numerical integration method, and a modified fifth-order S-curve planning algorithm is proposed to ensure the acceleration curve is smooth. Aiming at a minimum-time and minimum-jerk criterion, an optimal control system is designed to reduce the exchange time and overcome the default of controlling the acceleration mutation only by the minimum-time Bang-Bang control. Simulation and experiment results show that the exchange process can be realized by trajectory planning and optimal control method. The acceleration curve of modified fifth-order S-curve is the most smooth, and minimum-time and minimum-jerk optimal control system can achieve a shorter exchange time.