窄带滤光片与相干长度可调准单色光干涉研究

【作者】 刘洋；

【导师】 王青；

【作者基本信息】 南京理工大学 ， 光学工程， 2008， 硕士

【摘要】 随着半导体材料与器件、光盘技术和微光学、微机械、计算机和信息等产业的发展,表面质量的检测越来越引起人们重视,其中面形误差的检测是表面质量检测的重要内容。激光移相干涉技术是测量光学及半导体零件表面面形最常用的方法,但是在利用这种方法检测双抛光透明平行平板的面形时,将会出现三表面干涉现象,导致测量误差较大。针对这个问题本文提出了一种不对被测表面进行任何预处理且可实现低成本、高精度的测量方法,即使用白光光源和不同带宽的带通滤光片代替激光光源,通过更换滤光片来调节所得准单色光光源的谱线宽度,从而调节其相干长度,实现对不同厚度的双抛平行平板表面面形的测量。本文介绍了常见的带通滤光片薄膜的设计方方法,其中重点介绍了多半波法布里—珀珞滤光片的台伦设计法,并建立了相应的数学模型。利用所建立的数学模型求解了5nm和10nm带宽窄带滤光片的初始膜系,进而利用薄膜设计软件进行了模拟和优化。在制备薄膜之前,首先选择了TiO₂、SiO₂作为最佳镀膜材料,然后对其最佳的镀膜工艺参数进行了研究。在此基础上分别镀制了带宽50nm,10nm,和5nm滤光片,并对其透过率光谱和相干长度进行了测量。最后,利用所镀滤光片消除了三表面干涉现象,得到了所需的干涉条纹。更多还原

【Abstract】 With the development of semiconductor materials and devices, micro-optical disc technology, micro-machinery, computer and information industries, growing attention has be paid on the testing of the surface quality of the semiconductor and optical elements, including the surface error testing as an important item. Laser phase-shifting interferometry is one widely used method to test the surface of the semiconductor and optical elements, but when we use this method to test the surface of the daul-polishing transparent elements with parallel surfaces, there will be three-surface interference, leading to greater measurement error. To address this issue, this paper presents a method, which applies no pretreatment to the surfaces and can achieve low cost, high accuracy measurement, that replacing laser light source by white light source and different bandwidth band-pass filters. We can adjust the bandwidth of the quasi-monochromatic light source by changing filters, accordingly adjust its coherent length, and then achieve the surface testing of the daul-polishing transparent elements with parallel surfaces with different thickness.The commonly used design methods of the band-pass filter films are introduced in this paper, especially the Thelen design method of the Fabry - Perot filter with several cavities, correspondingly a mathematical model is established. Using the model we work out the initial film stacks of the 5 nm and 10 nm bandwidth filters, and then use film design software to do the simulation and the further optimization. Before the fabrication of the films, we firstly choose TiO₂, SiO₂ as the best coating materials, secondly study their best coating process parameters. On the basis of the studies above, we fabricate bandwidth 50 nm, 10nm, and 5 nm filters respectively, and then measure their transmittance spectrum and coherence length. Finally, we eliminate the three-surface interference with the help of the filters, and obtain the interference fringes we want.更多还原