Measurement of deformation of micro beam or thin membrane in Micro-electro-mechanical system(MEMS) has to be carried out by non-contacting device. In this study, a method is proposed to measure out-of-plane displacement of mirror surfaced thin film without contacting. This method, basically a shadow Moire, is applicable to mirror surfaced specimen. The specimen is circular-shaped Au membrane of 0.365 micron thickness and 3.5 mm diameter made by thermal evaporation of Au on silicon substrate of 500 micron thickness and subsequent removal of the silicon by eletropolishing.
The experiments are performed by blistering the specimen and measuring the out-of-plane displacement. The measured shape of the deformed membrane is approximated by a simple mathematical function, from which the Young's modulus, residual stress and rupture strength are obtained. In other to measure the interfacial toughness of Au/Si, a different blistering test seems to be necessary, which is discussed in this study.
