The main problem to be tackled when electronic devices are to be used is the proper dissipation of heat, from the joint to the external environment. The thermal organization can be divided as follows: - Thermal processes inside the device; - Heat transfer from the electronic device to the heat sink; - Heat diffusion from the heat sink to the outside In order to optimize the first two phases, it is very important to fully understand the heat diffusion modes as well as to know the material characteristics in detail.