Research

Three-dimensional topography measurement technology has important applications in ultra-precision machining and manufacturing fields such as integrated circuits, high-precision optical components, photovoltaic panels, and MEMS devices, serving as a quality assurance for ultra-precision micro-nano structural devices. optical interferometric measurement methods struggle to accommodate a large lateral field of view and a non-continuous height measurement range while maintaining measurement accuracy. However, the femtosecond optical comb, as a new type of broadband laser source, combines the high spatial coherence of continuous lasers with the low temporal coherence of white-light sources, bringing new to the field of surface profile measurement. The full-field three-dimensional topography measurement system based on the optical frequency comb studied by this research group adopts a non--arm large field-of-view interferometric optical path, achieves longitudinal scanning of the sample through scanning repetition rate, removes the mechanical scanning device in the optical, and proposes the synthetic wave method to achieve the transition from envelope peak coarse measurement to carrier phase precision measurement, tracing the step measurement accuracy back to single-wavelength phase. This system effectively combines the advantages of phase-shifting interferometers and white-light interferometers, achieving nanometer-level height measurement accuracy and hundred-micrometerlevel height range, while accommodating a large field of view, thus having good application prospects in the field of ultra-precision micro-nano manufacturing.