Interferometric Measurements of Piezoelectrically Driven Actuators

The ability to experimentally characterize static and dynamic deformation effects is crucial to the development of actuated MEMS and MOEMS devices. Almost all technological processes have an influence on the flatness and initial shape of microstructures. The accurate metrology plays a key role in the characterization and control of critical micro machining processes. For testing of MEMS structures the interferometric platform has been proposed. It gives the possibility to combine the capabilities of interferometric methods to measure static (e.g., initial shape, static out-of-plan displacements) and dynamic parameters of samples (e.g., resonance frequencies and amplitude distributions in vibration modes). In static case we use the conventional interferometry, while for vibrating elements the stroboscopic interferometry is applied with additional reference wavefront correction by a spatial modulator, namely liquid crystal on silicon (LCOS) element. As an exemplary results, the measurement of piezoelectrically driven silicon microactuators are presented