Rahlves Maik, Roth Bernhard, Reithmeier Eduard
Opt Express. 2015 Apr 20;23(8):9640-8. doi: 10.1364/OE.23.009640.
Optical aberrations of microscope lenses are known as a source of systematic errors in confocal surface metrology, which has become one of the most popular methods to measure the surface topography of microstructures. We demonstrate that these errors are not constant over the entire field of view but also depend on the local slope angle of the microstructure and lead to significant deviations between the measured and the actual surface. It is shown by means of a full vectorial high NA numerical model that a change in the slope angle alters the shape of the intensity depth response of the microscope and leads to a shift of the intensity peak of up to several hundred nanometers. Comparative experimental data are presented which support the theoretical results. Our studies allow for correction of optical aberrations and, thus, increase the accuracy in profilometric measurements.
显微镜透镜的光学像差是共焦表面计量中系统误差的一个来源，共焦表面计量已成为测量微观结构表面形貌最常用的方法之一。我们证明，这些误差在整个视场中并非恒定不变，而是还取决于微观结构的局部倾斜角度，并导致测量表面与实际表面之间出现显著偏差。通过全矢量高数值孔径数值模型表明，倾斜角度的变化会改变显微镜强度深度响应的形状，并导致强度峰值偏移高达数百纳米。给出了支持理论结果的对比实验数据。我们的研究有助于校正光学像差，从而提高轮廓测量的精度。
