The purposes of failure analysis are to localize the failure site, to establish the type of failure and to understand the failure mechanism. Some MEMS, such as Analog Device's accelerometer ADXL501, are confronted with stiction problems. Either we get around the problem by creating designs which are not subject to this type of failure, or we try to understand its mechanism. The residual stresses have an important role in the stiction because according to the configurations of the structures, they can stiffen beams and so oppose this failure, or amplify it by bending it towards underlying mechanical elements. That’s why we carry an interest in the residual constraints to understand and counteract this type of failure. Besides, the residual stresses have also repercussion on properties such as fatigue, fracture, friction... which are at the origin of other types of failure. In this article, we attempt to set up a method to qualify and quantify the residual stresses in the different layers of the MUMPs process.