Multi-channel Laser Interferometer for Parallel Characterization of MEMS Microstructures

In the paper the new approach towards microsystems characterization at wafer level, developed under EU project “SMART InspEction system for High Speed and multifunctional testing of MEMS and MOEMS” (SMARTIEHS) is presented. The goal of the project is to provide fast, cost effective and flexible optical inspection system. Two different interferometer approaches are pursued in the project’s development process: a refractive optics based Mirau type low coherence interferometer and a diffractive optics based Twyman-Green laser interferometer. In the paper the design and the tests of the laser interferometer are presented. The multifunctional approach of the interferometer measurement concept allows inspecting MEMS shape and deformation as well as characterizing spatial distribution of vibration amplitude at a resonance frequency within one instrument.