Journal of Materials Research


Two interferometric methods for the mechanical characterization of thin films by bulging tests. Application to single crystal of silicon

E. Bonnottea1, P. Delobellea1, L. Borniera1, B. Trolarda2 and G. Tribillona2

a1 Laboratoire de Mécanique Appliquée R. Chaléat, UA CNRS, UFR Sciences et Techniques, 24 chemin de l'Epitaphe, 25030 Besancon Cedex, France

a2 Laboratoire d'Optique, UA CNRS, UFR Sciences et Techniques, Route de Gray, La Bouloie, 25030 Besancon Cedex, France


Two optical methods are presented for the mechanical characterization of thin films, namely real time holographic interferometry and a fringe projection method called “contouring.” These two methods are coupled to the interferometry by the phase measurements, thus allowing the displacement field to be measured at all points on the membrane. We discuss the solutions retained in terms of their precision and sensitivity. These methods are then applied to membrane bulging tests, a type of test that is widely used in micro-mechanical studies. The measurements are performed on silicon single crystal and the results are compared to the solutions calculated by finite element methods. In both cases, the good agreement between theory and experiments allows the experimental apparatus to be validated.

(Received February 16 1996)

(Accepted May 08 1997)