Abstract
According to the fabrication processes, the thin film materials are normally under residual stresses. Unlike the microelectronics devices, the micromechanical structures are no longer constrained by the silicon substrate underneath after anisotropic etch undercutting. Therefore the residual stresses may lead to bending and buckling deformations of micromechanical structures. The buckling behavior has been exploited to measure the residual stresses of thin films. This characteristic can also be applied to fabricate out-of-plane three dimensional micromechanical structures, if their deflections are controllable.