Self-limited self-perfection by liquefaction for sub-20nm trench/line fabrication

We proposed and demonstrated a new approach to pressed self-perfection by liquefaction (P-SPEL), where a layer of SiO₂ is used as a stopper on one sidewall of gratings, to self-limit the final trench width in P-SPEL to a preset stopper layer thickness, allowing a precise control of the final trench width without the need to control any pressing parameters such as pressure, temperature and the gap between the pressing plate and the substrate. We achieved 20nm wide trenches from a 90nm original width, reducing the original trench by 450%. We also observed improvement in the trench width uniformity. Using the fabricated resist trenches as templates, 20nm metal lines were achieved by lift-off.