Through-focus scanning optical microscopy (TSOM) is a high-efficient, low-costed, and nondestructive model-based optical nanoscale method with the capability of measuring semiconductor targets from nanometer to micrometer level. However, some instability issues resulted from lateral movement of the target and angular illuminating non-uniformity during the collection of through-focus (TF) images restrict TSOM’s potential applications so that considerable efforts are needed to align optical elements before the collection and correct the experimental TSOM image before differentiating the experimental TSOM image from simulated TSOM image. An improved corrected TSOM method using Fourier transform is herein presented in this paper. First, a series of experimental TF images are collected through scanning the objective of the optical microscopy, and the ideally simulated TF images are obtained by a full-vector formulation. Then, each experimental image is aligned to its corresponding simulated counterpart before constructing the TSOM image. Based on the analysis of precision and repeatability, this method demonstrates its capability to improve the performance of TSOM, and the promising possibilities in application of online and in-machine measurements.

中文翻译：

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使用傅立叶变换的横向运动和角度照明不均匀校正的TSOM图像

透过焦点扫描光学显微镜（TSOM）是一种高效，低成本且无损的基于模型的光学纳米尺度方法，能够测量从纳米到微米级别的半导体目标。但是，由于目标的横向移动以及在通过全焦点（TF）图像收集过程中角度照明不均匀而导致的一些不稳定性问题限制了TSOM的潜在应用，因此需要在收集之前校正光学元件并校正实验来进行大量工作。将实验TSOM图像与模拟TSOM图像区分开来之前的TSOM图像。本文提出了一种使用傅里叶变换的改进的校正TSOM方法。首先，通过扫描光学显微镜的物镜收集一系列实验性TF图像，并通过全矢量公式获得理想模拟的TF图像。然后，在构造TSOM图像之前，将每个实验图像与其对应的模拟对应物对齐。在分析精度和重复性的基础上，该方法证明了其改进TSOM性能的能力，以及在在线和机内测量中应用的广阔前景。