Three-dimensional profile measurement of micro-electro-mechanical systems structures based on infrared light reflection interference

A new method of measuring the three-dimensional (3D) profile of micro-electro-mechanical systems (MEMS) structures based on infrared light reflection interference is developed in this paper. The application of reflection interference technology in a 3D profile reconstruction is extended from white light to infrared light. The measurement system comprised an infrared light source, an interference microscope, an infrared light charge-coupled device, a ceramic piezo and a data acquisition system. The 3D profile of the MEMS device structures was obtained by vertical scanning interferometry and it is consistent with the scanning electron microscope image. The results indicate that the lateral resolution is 0.18 um and the vertical resolution is 1 nm. (paper)