Development of a Microscopic 3-D Shape Measuring System Using Novel Liquid-Crystal Devices

本课题的研究目的是开发一种新的光谱干涉显微镜方案，该方案不需要机械运动部件，可以对结构复杂、高度不连续超过光波长的微观物体进行全方位三维形状测量。主要成果总结如下：1、研究成果。设计了近红外区可调范围为40nm的液晶法布里-珀罗干涉仪（lc - fpi），适用于与SLD相结合的光谱干涉测量，并通过数值模拟预测了其改进后的性能。制备了lc - fpi，并提出了串联使用lc - fpi在光谱干涉测量中有效提高整体精细度的建议。3 .基于LC-FPI和SLD（超级发光二极管）的组合使用，设计并构建了一种光谱干涉显微镜。系统控制和数据采集软件的开发开发了LC-FPI波长调谐控制的专用计算机代码，该代码与光谱干涉图的快速图像采集同步运行。光谱干涉显微镜性能的实验验证与评价利用在硅片上制作的1μm和11μm台阶的三维微结构，验证了所研制的光谱干涉显微镜的亚微米高度分辨率。

The purpose of this research project is to develop a new scheme of spectral interferometric microscopy that is free from mechanical moving components and can perform full-field 3-D shape measurement of microscopic objects with complex structures and height discontinuities exceeding the wavelength of light. The main accomplishments are summarized in the following :1. Design and Numerical Evaluation of Liquid-Crystal Fabry-Perot Interferometers (LC-FPIs)LC-FPIs with an extended tunable range of 40nm in the near IR region (which is suitable for spectral interferometry in combination with a SLD) were designed, and their improved performances were predicted by numerical simulations.2. Fabrication of LC-FPIs and Proposal of Their Tandem UseLC-FPIs were fabricated and their tandem use in spectral interferometry was proposed for effective improvement of the overall finesse value.3. Design and Construction of Spectral Interferometric MicroscopeA spectral interferometric microscope based on the combined use of an LC-FPI and a SLD (super luminescent diode) was designed and constructed.4. Development of Softwares for System Control and Data AcquisitionDedicated computer codes were developed for the wavelength tuning control of the LC-FPI that runs in synchronism to the fast image acquisition of the spectral interferograms.5. Experimental Demonstration and Evaluation of the Performance of the Spectral Interference MicroscopeSub-micron height resolution of the developed spectral interference microscope was demonstrated using a 3-D micro structure with 1μm and 11μm height steps fabricated on a silicon wafer.