基于对椭偏测量数据中难以消除的系统误差的作用机理分析，提出了一种新型的薄膜光学参数表征误差处理技术。建议选取薄膜椭偏角关于折射率和几何厚度的一阶偏导数，对大部分测量入射角满足符号相反或只有其中一个为零的条件的波段，剔除偏导数对全部测量入射角满足符号相同或同时为零的条件的奇点波长附近波段，作为反演表征用的椭偏测量数据采集区域，以最小化椭偏测量系统误差引起的薄膜光学参数反演表征值相对真实值的偏差大小。其本质是通过一阶偏导数筛选测量数据，来最小化椭偏测量系统误差对薄膜光学参数表征的误差传递作用。通过数值模拟实验，对比研究了该技术对不同测量入射角范围的适用性及实施技巧，以可复现的数值实验数据和合理的理论解释支持和验证了这种误差处理技术的可靠性，为薄膜在线表征和镀膜监控提供了一定的参考价值。

A novel errors treatment technique to optical-parameters characterization of thin films is presented based on the effect analysis of systematic errors which are hard to eliminate in ellipsometric measurement data. In order to minimize the characterization deviations of thin film optical parameters from the real values caused by ellipsometric measurement systematic errors, it is advised to select ellipsometric measurement data used in optical characterization from spectral bands characterized with opposite signs or single zero of first-order ellipsometric angles′ partial derivatives with respect to layer thickness and refractive index for most measurement incident angles, and to exclude spectral bands characterized with the same signs or both zeros of ellipsometric angles′ first-order partial derivatives for all measurement incident angles. The essence of this technique is to minimize the errors transfer effect of measurement data on thin-film optical-parameters characterization through spectral band selection of ellipsometric measurement by first-order partial derivatives analysis. Through numerical simulations, its applicability and selection skills of the range of measurement incident angles are compared and studied. The reliability of this technique is supported by resumable numerical experimental results and reasonable theoretical explanations. This novel errors-treatment technique provides a certain reference to in-situ characterization and thickness monitoring of thin films.