Development of Absolute Self-Calibration Systems for Displacement and Profile Measuring Instruments with Subnanometric Accuracy

本研究的目的是建立亚纳米精度的位移和轮廓测量仪器的绝对自校准系统。这类仪器的线性误差需要经常进行现场检定。在本研究中，我们首先提出了一种新的自校准方法。该方法只需测量数据即可获得线性度误差，不需要使用任何校准基准和额外的装置。在该方法中，校准曲线的导数是根据样品在传感方向上微小偏移前后的两个测量数据的差值来测量的。然后，可以通过对导数的积分来评估校准曲线。通过计算机模拟和几种仪器的标定实验，验证了该方法的可行性和准确性。经验证，该方法的标定误差小于被标定仪器分辨率的两倍。接下来，TH…更多的绝对校准是通过包括平均敏感度的校准进行的。为此，在样品夹中设置了专门设计的紧凑型激光干涉仪。在自校准法中，两次测量之间的偏移量被控制为干涉仪光源波长的几倍。结果，平均灵敏度可以以由波长的稳定性确定的精度来校准。通过对干涉仪显微镜的标定实验，验证了绝对定标方法的有效性。此外，还将自标定方法与提高STM/AFM精度研究项目中提出的外部监测方法进行了比较，两种方法的结果达到了较好的一致性，证明了自标定方法的可靠性。最后，建立了一种新的自主检测干涉仪波前误差的方法，该方法可以检测由于参照镜和光路失真引起的波前误差。该方法使用在样品的不同位置获得的两个表面和四个干涉图。较少

The purpose of this study is to establish absolute self-calibration systems for displacement and profile measuring instruments with subnanometricaccuracy. It is necessary to frequently calibrate the linearity error ofsuch instruments in situ. In this study, we first proposed a new self-calibration method. This method can obtain the linearity error by using only the measurement data, without using any calibration references and extra devices. In this method, the derivative of the calibration curve is measured from the difference of two measurement data obtained before and after a small shift of the sample in the sensing direction. The calibration curve can then be evaluated by the integration of the derivative. The feasibility and accuracy of this method was investigated by computer simulations and calibration experiments of several kinds of instruments. It was verified that the calibration error of this method is less than twice of the resolution of the calibrated instruments. Next, th … More e absolute calibration was performed by including the calibration of mean sensitivity. For this purpose, a specially designed compact laser interferometer, was set in the sample holder. The shift amount between the two measurements in the self-calibration method was controlled to be several times of the wavelength of the interferometer laser source. As a result, the mean sensitivity can be calibrated in an accuracy that is determined by the stability of the wavelength. The effectiveness of the absolute calibration method was confirmed by an experiment of calibrating an interferometer microscope. In addition, the self-calibration method has been compared with the external monitoring method, which had been proposed in a research project of improving the accuracy of STM/AFM.The results of the two method achieved a good agreement, and this proved the reliability of the self-calibration method. Finally, a theory of a new autonomous method, which can detect the wavefront error due to the reference mirror and optical path distortion in a interferometer, has also been established. This method uses two surfaces and four interferograms obtained at different positions of a specimen. Less