Corle T R, Kino G S
Appl Opt. 1990 Sep 10;29(26):3769-74. doi: 10.1364/AO.29.003769.
The first uses of Nomarski differential interference contrast imaging with the real time confocal scanning optical microscope are described. The advantage of differential interference contrast imaging in a confocal scanning microscope is that both the height and width of an edge can be measured without ambiguity, even if the edge is taller than half of a wavelength. Imaging modes are described in which (1) average reflectivity changes of the sample have been eliminated but the resulting edge enhanced images are nonlinear in phase, or (2) linear phase images are superimposed on an average reflectivity image of the sample. A third method has been developed which both eliminates the reflectivity image of the sample and generates edge enhanced images which are linear in phase for small phase changes. Applications to box-in-box overlay targets, imaging the passivation layer of an integrated circuit, and the measurement of sidewall slope are described.
本文描述了诺马斯基微分干涉对比成像技术在实时共聚焦扫描光学显微镜中的首次应用。在共聚焦扫描显微镜中，微分干涉对比成像的优势在于，即使边缘高度超过半个波长，也能明确测量其高度和宽度。文中介绍了两种成像模式：（1）消除了样品的平均反射率变化，但生成的边缘增强图像在相位上是非线性的；（2）线性相位图像叠加在样品的平均反射率图像上。还开发了第三种方法，该方法既能消除样品的反射率图像，又能生成在小相位变化时相位呈线性的边缘增强图像。文中描述了该技术在盒中盒覆盖目标、集成电路钝化层成像以及侧壁斜率测量方面的应用。
