In the future, the peak temperature of a chip will be a primary design constraint. In order to meet this constraint, temperature must be considered in the earliest phases of the design process. Using a newly developed thermal analysis tool, HS3d, this work explores the thermal profile of devices as technology varies. We show that as technology scales, the hotspot locations can shift from the units with the most switching activity to those with the most lowthreshold transistors. We further note that process variations in leakage dominated technologies can result in significant variations in the hotspot locations, indicating that feedback from thermal sensors will be very important. Finally, this work examines the thermal effects of multi-layer device stacking technologies, and finds that the vertical temperature difference between layers is much less significant than the horizontal differences due to power density, and as such, vertical placement optimizations will have much smaller impact on hotspot development than a uniform power distribution.