2 INTERFEROMETRIC METHODS FOR THE MECHANICAL CHARACTERIZATION OF THIN-FILMS BY BULGING TESTS - APPLICATION TO SINGLE-CRYSTAL OF SILICON

Two optical methods are presented for the mechanical characterization of thin films, namely real time holographic interferometry and a fring e projection method called ''contouring.'' These two methods are coupl ed to the interferometry by the phase measurements, thus allowing the displacement field to be measured at all points on the membrane. We di scuss the solutions retained in terms of their precision and sensitivi ty. These methods are then applied to membrane bulging tests, a type o f test that is widely used in micro-mechanical studies. The measuremen ts are performed on silicon single crystal and the results are compare d to the solutions calculated by finite element methods. In both cases , the good agreement between theory and experiments allows the experim ental apparatus to be validated.