Metrology, static and dynamic characterization of microstructures using acousto-optic-modulated-stroboscopic-interferometry

Mechanical and electro-mechanical advancements to the nano-scale require comprehensive and systematic testing at the micro-scale in order to understand the underlying influences that define the micro/nano device both from a fabrication and operational point of view. In this regard, surface metrology measurements, as well as static and dynamic characteristics will become very important and need to be experimentally determined in order to describe the system fully. These integrated tests are difficult to implement at dimensions where interaction with the device can seriously impact the results obtained. Hence, a characterization method to obtain valid experimental information without interfering with the functionality of the device needs to be developed. In this work, an Acousto Optic Modulated Stroboscopic Interferometer (AOMSI) is presented and employed to obtain surface, static and dynamic properties of micro-scale structures. This method has the advantage of being a high-speed visualization technique that can provide details of surface metrology as well as static/dynamic displacements and modal profiles. In this regard, it is a non-contacting approach that can be implemented without negatively impacting structurally sensitive devices especially at the nano-scale. The experimental setup can incorporate both thermo-mechanical and electro-mechanical loading in order to quantify operational and/or environmental influences. This method has the advantage of obtaining real time vibrating shape modes when compared to single point scanning methods. This approach is applied to cantilever microstructures. Sample test results are presented and compared with theory and are in good agreement.