光谱法测量薄膜厚度算法的改进

提出了一种计算薄膜厚度的单极值点算法。在对SiO2二氧化硅薄膜的测试中，该测试方法与椭圆偏振仪的测试结果相对照，纵向测量误差小于2nm．讨论了双极值点算法计算薄膜厚度，对薄膜的反射干涉光谱曲线进行了分析。主要讨论了薄膜材料色散对测试精度的影响，在此基础上对算法进行了改进，最终利用单个极值点的数据计算出薄膜的厚度。该方法和双极值点算法相比较，其优点在于考虑了薄膜材料的色散对测试结果带来的影响，通过精确定位光谱曲线上的极值点阶数和选择合适的极值点，达到了很好的测量精度。

Improving on Calculating Film Thickness by Spectrum Analysis

A method to calculate thickness of film by single apex is introduced. In the testing for silicon dioxide film, the thickness testing error is within 2 nm compared with the results obtained from ellipsometry. The old method which thickness of film is calculated by two apices is discussed, and the reflected interference pattern of film is analyzed. Dispersion of film material which affects testing precision greatly is discussed, and calculate method is improved. Thickness of film is obtained by using data of a single apex. The method has the advantages over the old is in that dispersion of film is considered. By calculating the grade of apices accurately and choosing a right apex, testing precision is high.