Characterization of the static and dynamic behaviour of M(O)EMS by optical techniques: status and trends

Optical techniques which were developed for ex situ characterization of static displacements, motions, vibrations and internal strain of micromechanical devices and M(O)EMS are critically reviewed. Their performances and limitations are analysed and improvements which were proposed recently and which are still needed are discussed. It is shown that many optical techniques are available for 1D, 2D or 3D out-of-plane measurements with a lateral resolution in the (sub)micron range, a vertical resolution in the (sub)nanometer range and a frequency range up to a few MHz or more. In contrast, only very few techniques are suitable for in-plane, on wafer or in vacuum measurements.