计量型激光椭偏仪初始入射角校准方法的研究

为保证计量型激光椭偏仪测量结果的准确性,研究了一种初始入射角校准方法,通过线性位移台带动CCD相机进行一维运动,其运动轴作为空间线性辅助参考量,实现了椭偏仪的入射激光光轴与自准直仪光轴的90°校准。结果表明:采用该方法校准计量型激光椭偏仪的初始入射角,光轴俯仰角偏差＜0.05°,偏摆角偏差＜0.09°;校准后,对标称值为102.10nm的Si上SiO₂膜厚标准片进行测量,示值误差＜0.4nm,提升了计量型激光椭偏仪测量校准服务的准确性。

Research on Calibration Method of Initial Incident Angle of Metrological Laser Ellipsometer

To ensure the accuracy of the measurement results of the metrology-type laser ellipsometer, an initial incidence angle calibration method is investigated, the incident laser optical axis of the ellipsometer is calibrated at 90° to the optical axis of the self-collimator by means of a linear displacement stage driving the CCD camera in one-dimensional motion, and its motion axis is used as a spatial linear auxiliary reference quantity. The results show that the initial incidence angle of the metrology-type laser ellipsometer is calibrated by this method, and the deviation of the optical axis pitch angle is less than 0.05° and the deviation of the deflection angle is less than 0.09°. The calibration results show that the calibration error of the SiO₂ film thickness standard on Si with the nominal value of 102.10nm is less than 0.4nm. The research work has improved the accuracy of the measurement and calibration service of the metrology-type laser ellipsometer.