Energy study of buckled micromachined beams for thin-film stress measurements applied to SiO2

Abstract

Measurements of maximal deflection amplitude were carried out on arrays of clamped-clamped SiO2 microfabricated beams buckling under the effect of thin-film built-in compressive stress. The experimental deflection determination of these deflections yields the residual stress value in the SiO2 film. This proposal is confirmed by appropriate theory that considers the issue of microfabricated beam buckling from an energy point of view. In this model, the total potential energy stored in a buckled microbeam is computed and the residual stress value is given by considering the measured buckling maximal deflection and by making approximations about the shape of the microbeam deflection curve. The SiO2 film residual stress evaluated with the help of the energy method is in good agreement with values reported in the literature.