The mechanical stresses induced by adsorption or desorption of water from various dielectric films (vitreous silicate glass, phosphosilicate glass, borophosphosilicate glass, and spin on glass) are analyzed in terms of two-dimensional finite-element simulations. For this, a new model that predicts the stress induced by the adsorption or desorption of water in the films (i.e., the extrinsic stress) has been added to a general algorithm dedicated to the calculation of stresses in silicon processes. This model was calibrated for (un)doped silicate glasses and spin on glass. Thanks to this work, a mechanical study and optimization of back-end processes, including all sources of stress, are now available. It is shown that the stresses developed in densified spin on glass can be very high and are likely to degrade the reliability of devices planarized by these techniques.