Les interféromètres de type Mirau sont largement utilisés dans les profilomètres et vibromètres optiques 3D plein champ et d’autres applications dans les domaines de la biologie et de la médecine ont été démontrées. Quand elle a été débutée, cette thèse était la première tentative de réalisation d’interféromètres Mirau entièrement intégrés et accordables en technologie microsystèmes électromécaniques (MEMS) silicium. La conception proposée est fondée sur l’intégration hybride 3D d’un wafer de scanners hors plan de micromiroirs de référence et d’un wafer de séparatrices de faisceaux optiques. La nouveauté majeure de la conception du scanner de miroir est l’utilisation de microactionneurs à peignes électrostatiques verticaux autoalignés réalisés à partir de wafers double Silicium sur Isolant (DSOI). Les modélisations semi-Analytiques et les simulations électromécaniques par éléments finis ont démontré que la combinaison de cet actionnement électrostatique avec des ressorts en serpentins optimisés permet d’obtenir une translation de grande course, bidirectionnelle et symétrique (+/-20µm) du miroir de référence. Un procédé de fabrication original de ce scanner de miroir, reposant largement sur la gravure ionique profonde (DRIE) et des techniques innovantes de délimitation de motifs avec des films secs photosensibles, a été étudié, et les principales étapes critiques de fabrication ont été démontrées avec succès avec des substrats de Si, SOI et DSOI commetciaux. La séparatrice semi-Réfléchissante large bande a été conçue pour être réalisée par une technologie de fabrication de membranes diélectriques multicouches SiO2/SiNx développée précédemment à l’IEF. L’assemblage des wafers de scanners de miroir et de séparatrices sera étudiée dans l’avenir pour obtenir des matrices d’interféromètres Mirau accordables permettant des mesures parallélisées d’interférométrie à décalage de phase ou d’interférométrie faiblement cohérente à balayage dans différentes gammes de longueurs d’onde. / Mirau-Type interferometers are widely used in full field optical 3D profilometers and vibrometers and other applications in biology and medicine fields have been demonstrated. When it was started, this thesis was the first attempt towards the realization of a fully integrated and tunable Mirau interferometer in silicon MEMS technology. The proposed design is based on 3D hybrid integration of an out-Of plane reference micro-Mirror scanner wafer and a optical beam splitter wafer. The major novelty of the micro-Mirror scanner design is the use of self-Aligned vertical electrostatic combs micro-Actuators made from double SOI (DSOI) wafers. Electromechanical modeling by semi-Analytical modeling and finite element simulations demonstrated that the combination of this electrostatic actuation with optimized serpentine suspension springs allows a large range, bidirectional and symmetrical vertical translation (+/-20µm) of the reference mirror. An original fabrication process of this mirror scanner, largely relying on Deep Reactive Ion Etching and on innovative patterning techniques with dry photosensitive films, was investigated, and the main critical fabrication steps were successfully demonstrated with commercial Si, SOI and DSOI substrates. The semi-Reflective broadband beam splitter was designed to be realized by a dielectric SiO2/SiNx multilayer membrane technology previously developed at IEF. Assembly of the mirror scanner and the beam splitter wafers will be investigated in the future to obtain integrated tunable Mirau interferometer arrays allowing parallelized phase shifting interferometry and low coherence scanning interferometry measurements in various wavelength ranges.

Biomechanics, an emerging science, refers to the mechanical characterization of biological tissues. Recent work published in this field demonstrate the role of mechanical processes and properties on the biological tissues functionalities, and especially at the microscopic scale (cell biomechanics). Biomechanical data acquisition is however quite challenging. This requires appropriate measurement tools (for forces, strain, ...) to cope with the biological sample and environment constraints (biocompatibility, size, anisotropy, ...). In parallel, the fast developments observed these last years in microtechnologies lead to interesting research possibilities. The family of MEMS [MicroElectroMechanical Systems] devices for instance introduces a new potential of interaction with the microscopic world. The integration of this technology in the field of cellular biomechanics is thus a natural choice. In that context, this work aims to design a 3-axis microforce sensor to measure biological tissues deformations at the microscopic scale. The MEMS device, fabricated on SOI [Silicon on Insulator] wafers, is based on piezoresistive and capacitive force transductions. It can be used as an actuator at least in one direction. This thesis describes the design, fabrication and test of the 3-axis system. A 1-axis prototype, exclusively capacitive, is first realized and acts as the foundation of the 3-axis device. The 1-axis force sensor, tested on the [0 ? 350[mu]N ] range shows a sensitivity in the order of 4.85mV/[mu]N (G=2000) and a resolution of 1.24[mu]N (linearity until 100[mu]N ). A new 3-axis geometry is then proposed to improve the direction decoupling efficiency of 2-axis capacitive sensors presented in publications and add a third detection axis. The decoupling is achieved using a"two frames" geometry and piezoresistors implanted in a configuration only sensitive to an out-of-plane loading. The three transducers performances are analysed individually. Tested on a range of 250? N , the sensors show a linear behaviour on the whole forces domain in the out-of-plane axis (piezoresistors) and until 100[mu]N in the in-plane direction (electrostatic combs). The piezoresistive and capacitive transducers are characterized by sensitivities of 0.93mV/[mu]N (g=400) and 6.35mV/[mu]N (G=500) respectively (on the linear part), with resolutions of 7[mu]N and 0.161[mu]N. The dynamical behaviour of the sensor allows its use above the kHz. The cross-talk sensitivities of each transducer are evaluated to 1-5% of their axis sensitivity (decoupling). The work presented in this thesis demonstrates the feasability of a 3-axis MEMS force sensor based on capacitive (in-plane sensing) and piezoresistive (out-of-plane sensing) detection. The proof of concept refers to the fabrication and performances (sensitivity, resolution, decoupling) of the proposed design.