光纤白光干涉法与膜厚纳米测量新技术研究

运用薄膜光学干涉原理、光纤技术和干涉光谱分析技术,用光纤反射式干涉光谱仪(Reflectromic Interference Spectroscopy)直接测试宽带入射光在单晶硅表面超薄SiO₂膜层前后界面反射形成的干涉光谱曲线,并用专业软件对被测光谱信号数据处理后,可直接用公式准确计算出SiO₂氧化膜的厚度和光学折射率通过对单晶硅片表面超薄SiO₂氧化膜的实测,并与成熟的椭圆偏振仪测试结果相比,测试误差≤2nm但该方法测试简单、快速,精度高,不需要制定仪器曲线和数表,可对薄膜任意位置的厚度在线测试经过对不同厚度聚苯乙烯薄膜的厚度测试表明,该方法适合0.5～20μm薄膜厚度的精确在线测量,测量误差小于7nm.

Study of Nanometer Scale Thickness Testing Method of Film Based On The White-light Interferometry

According to the theory of white-light interference spectrum analysis and optical fiber technology, using reflectromic interference spectroscopy setup made by our group, the thickness and its refractive index of SiO₂ film can be directly calculated by analyzing the spectrum formed between the two reflected light at two interface of the film with professional software. Comparing the testing results with ellipsometry method’s, the testing error is less than 2 nm. But, this method is fast and easy in operation, accurate. Using this method, the thickness and refractive index of film can be tested on line. The experimental testing results of SiO₂ film and polystyrene film show that the sensitivity of this method is from 0.5nm to 20 μm, test error is less than 7 nm.