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提出一种精确检测光刻机激光干涉仪测量系统非正交性的新方法.将对准标记曝光到硅片表面并进行显影;利用光学对准系统测量曝光到硅片上的对准标记理论曝光位置与实际读取位置的偏差;由推导的位置偏差与非正交因子、坐标轴尺度比例、过程引入误差的线性模型,根据最小二乘原理计算出干涉仪测量系统的非正交性.实验结果表明,利用该方法使用同一硅片在不同旋转角下进行测量,干涉仪测量系统非正交因子的测量重复精度优于0.01μrad,坐标轴尺度比例的测量重复精度优于0.7×10-6.使用不同的硅片进行测量,非正交因子的测量再现性优于0.012μrad,坐标轴尺度比例的测量再现性优于0.6×10-6.
A new method for accurately detecting the non-orthogonality of measuring system of laser interferometer is put forward. The alignment mark is exposed to the surface of the silicon wafer and developed. The optical alignment system is used to measure the alignment mark theory The deviation of the exposure position from the actual reading position; and the linear model of the error introduced by the derived position deviation and non-orthogonal factor, the scale of the coordinate axis and the process introduction error, calculates the non-orthogonality of the interferometer measurement system according to the principle of least squares. The experimental results show that the method uses the same silicon wafer to measure at different rotation angles, the measurement repeatability of the non-orthogonal factor of the interferometer measurement system is better than 0.01μrad, and the repeatability of the scale ratio of the coordinate axis is better than 0.7 × 10- 6. The measurement of non-orthogonal factors is better than 0.012μrad using different silicon wafers, and the reproducibility of the scale ratio of the axes is better than 0.6 × 10-6.