双池算法软件在对准偏差计算中的应用

Bi-Cell Detector Algorithm for Calculating Misalignment

提出了一种高精度的对准偏差算法─—双池算法。根据这种算法，将暗场对准系统中扫描采集的光电对准信号，通过求出整个扫描曲线的对称点以代替传统的极值点或阈值点，使重复对准精度达０．１１μｍ（３σ）。文中对双池算法的原理、特点及数学表达式进行了详细的论述，并给出了实验结果。

A unique alignment algorithm-hi-cell algorithm is presented. With the alignment scan curve generated from the dark field alignment system, a bi-cell detector implemented in software is used for calculating the misalignment. In the bi-cell detector algorithm the symmetry point over the alignment scan curve is calculated as the ideal alignment point instead of the peak value point or other characteristic value point. Results show that the alignment accuracy better than 0. 11 μm (3) can be obtained. The principle, features and mathematical formulas of the algorithm are described in detail.