基于灵敏度分析的一维纳米结构光学散射测量条件优化配置

Optimization of measurement configuration in optical scatterometry for one-dimensional nanostructures based on sensitivity analysis

在光学散射测量中,除了实际测量光谱的质量外,模型的输出光谱对待测纳米结构参数的灵敏度也对最终测量结果的精度具有重大影响.由于不同的测量配置(入射波长、入射角和方位角的组合)下,纳米结构参数的灵敏度会不同,因此提出了一种基于灵敏度分析的测量条件优化配置方法来改善待测参数的灵敏度,以实现更高精度的纳米结构测量.实验表明,在理论预估的最优测量配置下,一维纳米结构所有待测参数的测量精确最优,验证了其有效性.

In optical scatterometry,the sensitivity has a significant impact on the precision of the extracted structral parameters in addition to the quality of the measured signatures. As the sensitivity of structral parameters can be improved with the proper selection of measurement configuration（ a combination of wavelengths,incidence,and azimuthal angles）,we proposed a method to determine an optimal one for optical scatterometry based on sensitivity analysis. Experiments performed on a one-dimensional periodic grating showagreement between the theoretically predicted and experimentally obtained optimal measurement configurations,which demonstrates the validity of the proposed optimization method.