Large-Scale Thermal TCAD Simulations of 7nm Circuits

Many IC thermal simulations use only a small volume due to machine/EDA tool constraints. This work presents a thermal TCAD simulation methodology on a large-scale 7nm circuit using available thermal TCAD tools. The circuit model is based on a 3 x 3 array of inverter circuits and incorporates 18 metal levels in the back-end. A constant power is applied to each channel of the devices in the inverters as the heat source. The steady-state temperature is calculated for the system, with the goal of ensuring the temperature in the metallurgy does not exceed electromigration limits. Furthermore, the overall volume modelled is enlarged to evaluate the TCAD tools abilities to scale to larger and more complex models. The model, the methodology used and the results with specific attention to the scalability of the tools evaluated is discussed. The applicability of this methodology is demonstrated by showing the self-heating of measured structures is predicted with reasonable accuracy.