As the demand increases to build high performance systems, trends in electronic package design have moved toward larger circuit chips, higher number of I/O ports, increased circuit density, and improved reliability. Greater circuit density means increased power density (W/cm ). The power density has increased exponentially over the past 15 years and it appears that it will continue to do so in the near future. As the power density is high with 3D technology, the thermal management should be considered carefully in stacked devices. However, thermal management issues are normally technology specific and it is one of the characteristics which could be used to distinguish between packaging technologies. Note that design environment software provides a means to estimate the device thermal energy, and a means to evenly distribute the thermal energy across the device, leading to an efficient power dissipation.