Super-Resolution Three-Dimensional Topography Measurement Using Microsphere-Aided Broadband Light Interferometry

With the rapid development of the information era and super-precision fabrication technology, micro/nano technology has already become one of the most important modern scientific directions. To quantitatively characterize the defects, uniformity, quality and performances of micro/ nano devices, three-dimensional topography measurement plays a key role and has become increasingly 6important. In this paper, we proposed a microsphere-aided Mirau-based broadband light interferometry method to achieve super-resolution 3D topography reconstruction. We numerically and experimentally demonstrated that dielectric microspheres, which can introduce the phenomenon of photonic nanojet, could break the optical diffraction limit and achieve super-resolution microscopy under white light illumination. The subwavelength samples, which could not be detected by conventional microscopy, were clearly visualized by the proposed microsphere-aided microscopy. Furthermore, we applied the advanced Stoilov five-step phase shifting method to reconstruct the 3D topography. The experiment results demonstrated that our proposed microsphere-aided broadband light interferometry method could successfully reconstruct the 3D shape of nanoscale cylinders with the feature size of 228 nm and height of 150 nm with an error of 2%. As microsphere is a low-cost, easy-to-use, and super-resolution imaging method, it bears great potential to be widely applied in both scientific and industrial areas. We believe that our proposed super-resolution three-dimensional topography measurement using microsphere-aided broadband light interferometry will be of great interests in semiconductor, material, laser eavesdropping, extreme fabrication and biomedical applications.