步进扫描光刻机硅片台连续扫描时间优化算法

Time-optimal Algorithms for Continuous Scans of Wafer Stage of Step-scan Lithography Tool

为减少步进扫描光刻机连续曝光扫描运动的扫描过渡时间(扫描时间和步进时间),将硅片台扫描方向曝光扫描运动分解为逻辑步进运动和逻辑扫描运动,提出扫描和步进运动时间重叠的轨迹规划算法(时间重叠算法)处理连续曝光扫描运动。在不破坏运动约束条件下(恒速运动要求以及速度、加速度边界限制),根据时间重叠算法重新计算并推导不同扫描运动路径下连续扫描运动过程的步进和扫描运动转折点。经理论分析和硅片曝光场连续曝光实例计算表明:基于时间重叠算法的轨迹规划可获得时间优化的硅片台连续曝光扫描,比传统扫描方法减少曝光扫描运动过程中的无效率时间,提高步进扫描光刻机生产率,为步进扫描光刻机工程实践提供理论基础。

In order to reduce the scanning transitional time （including scanning time and stepping time） between continuous exposure scans of step-scan lithography tool in a production process, the exposure scan motion of the wafer stage in the scanning direction is divided into two parts： the logical step and the logical scan. The time-overlay algorithms are introduced in trajectories scheming for wafer stage to process the continuous exposure production. According to the algorithms the switching points of the logical scan and the logical step trajectories of continuous scan motions are recalculated under different scanning paths of exposure fields, which will not violate the motion limitations （the requirement of constant velocity during exposure scan and the limitations of acceleration and velocity in logical scan and logical step motions）. The theoretical analysis and actual wafer exposure examples calculation show that the time-optimal trajectories of wafer stage for continuous exposure scans are obtained by the time-overlay algorithms. And the inefficiency time between exposures scans schemed by the proposed algorithms is less than that of the conventional exposure scan methods. Consequently the productivity of the wafer production of step-scan lithography tool is improved. It is also fully expected that these research tasks will provide a valuable theoretical foundation for improving the throughput of wafer exposure of step-scan lithography tool in the practical enginecring.