Exploring the Benefits of Cryogenic Temperatures for Co and Ru Metallizations

We benchmarked Co and Ru metallizations against Cu at cryogenic temperatures (5K-300K) by using imec resistivity model and actual interconnects, with widths between 14 and 64 nm. We observed a decrease in resistance as temperature decreases, with Ru and Co exhibiting the largest drop (~50%) due to their larger Temperature Coefficients of Resistance (TCR). For 20nm-wide lines, the calculated TCR was ~2000 ppm/°C for Ru and Co compared to ~1000 ppm/°C for Cu. However, we show that only Ru outperforms Cu, with the cross-over occurring at 100K for 26nm-wide lines, potentially boosting the performances of systems operating at cryogenic temperatures.