Analytical Multistage Thermal Model for FEOL Reliability Considering Self-and Mutual-Heating

Aggressively scaled devices with high power density wrapped around the low thermal conductivity material in narrow space are susceptible to self-heating effect, which includes serious mutual-heating due to proximity effect in multifinger/fin FETs. Obtaining local temperature instead of equivalent lumped temperature at device/circuit level quickly is crucial for designers to accurately predict front-end-of-line reliability (i.e., hot carrier injection, bias temperature instability, and time dependent dielectric breakdown) and achieve better thermal management. In this paper, we: 1) first propose an analytical model based on multistage thermal network to address effectively the self- and mutual-heating within the device; 2) validate the multistage network and proposed analytical model by COMSOL and SPICE simulation, respectively; and 3) utilize the model to investigate local temperature rise in multifinger and multifin FETs-based inverter and ring oscillator as well as provide thermal-aware IC design guideline for self-heating and reliability optimization. The results show that the analytical multistage thermal model can predict local temperature rise and quantify nonuniform temperature difference in full-frequency range, superior to the lumped thermal model. Moreover, the model can offer quick thermal analysis at the pre-Si stage for reliability prediction and thermal-aware design.