We investigated open Through Silicon Via (TSV) technology for 3D integration based on tungsten, which was introduced for the first time in 2010 by ams company. Although much progress has been made in the mechanical characterization of the TSV's structure since then, the stress development along the metal layer remains unclear. Furthermore, direct measurement of the stress in this TSV is rather challenging and during device processing some plasticity of the thin-film metal layer (tungsten) is expected, due to temperature variations from room temperature up to 500°C. Our goal is to provide a better understanding of the deformation in the tungsten layer of this open TSV technology and to estimate its impact on device mechanical stability during processing. Therefore, we propose in our work a simulation scheme based on the Finite Element Method (FEM) to model the via's metal plasticity and to understand the stress behavior. X-Ray Diffraction (XRD) stress measurements were performed on the metal layers of this structure during a thermal cycle with a maximum temperature of 500°C at a rate of 1°C/min, and for each step the measured stress was recorded. We inferred from these data, and also from other results of thin film modeling, that the stress behavior can be explained by the dislocation glide mechanism, which causes low temperature plasticity. A FEM simulation was subsequently set coupling the plastic and the thermo-elastic model. The stress evolution in the TSV top has a distinct behavior for the two different in-plane directions, unlike planar thin film samples. We concluded that the thermal stress in the cylindrical-shape TSV superposes the expected stress evolution, leading to a fast decline of stress in the tangential direction and a very slow growth in the vertical direction. Hence, the von Mises stress has a peculiar behavior; during the heating it follows the upper branch of the temperature-stress curve (see picture) as the stress component in the vertical direction of the TSV structure does, and during the cooling it follows the bottom branch of this curve, as the stress component in the tangential direction does. Moreover, the magnitude of the von Mises stress never surpasses the initial value, which can be used as an estimation for the maximum stress during the thermal cycle. The simulated results are compatible with the experiments and verify our approach to the problem. The stress inside the TSV follows a particular evolution due to the influence of the geometry deformation during temperature variation. From our simulations and analysis of von Mises stress inside TSV during temperature cycling, we conclude that the stress never grows beyond its initial value. This information is vital for the proper assessment of mechanical stability of the device.