Reflective property of typical microstructures under a white light interferometer

This paper studies the reflective property of several typical microstructures while a white light interferometer (WLI) is used to measure them. Siemens stars, gratings with rectangular profile and atomic force microscopy cantilevers are measured under the WLI. To compare with the measurement results, the propagation behavior of white light reflection on the surface with micro-objects is simulated numerically on the basis of Maxwell's equations. An interference which is contrived by the steep edges of the surface structures is recognized. This interference plays a key role with the surface plasmon (Raether H 1988 Surface Plasmons ed G Hohler (Berlin: Springer)) when the reflective light does not follow the law of reflection in the area close to the structure edges. The above phenomenon could lead to a measuring error, a decrease in lateral resolution, inducing vertical measuring uncertainty, or even a non-measured signal when using the WLI.

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