The Determination of Mechanical Parameters and Residual Stresses for Thin Films Using Micro-Cantilever Beams

A method for determining mechanical parameters and residual stresses for thin films is described. Multi-layer cantilever beams (LPCVD SiN x /thermal SiO 2 ) are fabricated utilizing standard IC processing technologies and micromachining of silicon. The elastic response of the beams to imposed deflections is then measured using a Nanoindenter, a sub-micron hardness testing machine. The elastic constants of the nitride films are calculated from the force vs. deflection slope and known elastic constants of the thermal SiO 2 and silicon. By measuring the curvature of the multi-layer cantilever beams with a scanning electron microscope after successive etching of the LPCVD nitride films, average and differential stresses in the films were calculated.