Interferometric method for characterizing the mechanical properties of thin films by bulging tests

A fringe projection method (contouring) is applied for the mechanical characterization of thin films by bulging tests. This method is then coupled with the technique of phase modulation (phase shifting interferometry) thus allowing the phase image of the membrane, hence the displacements at all points, to be determined. We discuss the precision and the sensitivity of the method. This technique is then applied to membrane bulging tests performed on single silicon crystals, on thin Si-SiO2 films and on electro-deposited nickel. For these materials, the Young's moduli and the internal stresses resulting from the fabrication process are determined and compared with the values obtained by other methods. The examples presented allow the principle of the bulging test and the apparatus to be validated.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.