用于曲面光栅刻蚀的工作台轨迹拟合及测试误差分析

制作高闪耀角一致性的曲面闪耀光栅需要工作台能够进行曲线拟合运动,因此针对曲面闪耀光栅离子束刻蚀机三维工作台的控制算法开展研究。首先,介绍了曲面闪耀光栅离子束刻蚀机三维工作台的原理方案。接着,根据曲面刻蚀机的实际使用要求,给出了工作台运动轨迹的理论计算方法。然后,提出了一种适用于工作台的圆弧拟合算法,实现了工作台所需的曲线拟合运动。最后,在多组工作参数下开展了三维工作台运动轨迹的测量实验,并将理想轨迹与实测轨迹进行了对比。实验结果表明:工作台进行15个周期的直线拟合运动的累积定位误差小于0.218mm,角度误差小于0.02°;进行40个周期的曲线拟合运动的累积定位误差小于0.2mm,转角误差在-0.2°~0.1°。此方法实现了三维运动工作台扫描刻蚀与摆动刻蚀的功能,工作台的稳定性、精度、抗干扰能力满足设备使用要求。

Trajectory-fitting and testing error analysis of stage for curved grating etching

To manufacture curved surface gratings with highly consistent blazing angles, the curve-fitting motion of the three-dimensional (3D) stage is essential. Therefore, an investigation of the 3D stage was performed based on a control algorithm for the curved blazed grating etching system. First, a concept of the 3D stage of the curved blazed grating etching system was introduced. Subsequently, according to the actual requirement of the etching machine, the theoretical calculating method for the track of the stage was provided. Then, the arc-fitting algorithm of the stage was proposed and the curve-fitting motion of the stage was performed. Finally, the actual motion tracks of the 3D stage were measured and compared with ideal tracks. Experimental results demonstrate that the cumulative positioning error of the linear fitting motion of the stage after 15 cycles is less than 0.218 mm, and the slope angle error is less than 0.02°; the cumulative positioning error of the curve fitting motion of the stage after 40 cycles is less than 0.2 mm and the rotating angle error is in the range of -0.2°-0.1°. This method has realized the function of scanning etching and oscillating etching of the 3D stage. The stability, accuracy, and interference rejection of the stage satisfy the processing requirements.