4.3  Evaluating TSVs’ Mechanical Impact

During operation, the device is expected to work properly in the temperature range of -40C to 125C. The goal here is to assess the mechanical response of the structure in this scenario considering a stress free temperature of 25C, although, the existence of residual stress in the metal layer of the TSV is known [85]. Pre-stress in elastic simulations would only bias the final stress without major modifications to the general behavior. Furthermore, residual stress has a much more local effect as will be described in Chapter 5. Plasticity was also neglected, because its effects are destructive for the devices in silicon. Therefore, any TSV design should keep the stress in the silicon below the plastic threshold.