Etude et mise au point de techniques opto-numériques pour la caractérisation des paramètres mécaniques de composants MEMS/MOEMS

The PhD dissertation was performed under the agreement of co-tutelle between Universite de Franche-Comte (France) and the Warsaw University of Technology (Poland). A very broad field of relevant technologies and testing of silicon micromechanical elements had to be limited to specific elements and experimental methods. Two type of microelements have been selected: micromembranes (monolayers and bimorphs), and polysilicon Scratch Drive Actuators (SDA). Due to mirror type reflection of silicone, two-beam interferometry with computer aided interferogram processing has been selected for shape and deformation of the microelement surface, while the nanoindentation has been used for the extraction of micromechanical properties such as hardness and Young's modulus. Firstly, we investigated silicon membranes prestressed by SiOxNy films. The combination of numerical calculations (FEM) with experimental studies gives powerful methodology for residual stress determination. The distribution of residual stress was monitored as a function of the refractive index of SiOxNy films, establishing the correlation between the optical and micromechanical properties of deposited thin films. In second application the object to be measured was SDA actuator. Actuators require specific tools to verify that their mechanical properties and motions obey the designer's intent. In this dissertation capabilities of future direct-drive electrostatic actuators SDA are investigated through the characterization of their out-of-plane displacements by interferometry. Additionally, the results from interferometric method are compared with numerical simulations given by finite elements software - ANSYS.