EUV Resist Process Performance Investigations on the NXE3100 Full Field Scanner

摘要

Extreme Ultraviolet (EUV) Lithography is a candidate for device manufacturing at the 22nm half pitch node and beyond. The key challenge for EUV resists remains to simultaneously meet the requirements for Sensitivity, Resolution and Line-edge-roughness (LER) for Line/Space features (LS), respectively local CD uniformity (LCDU) for Contact holes (CH). The introduction of the ASML NXE:3100 pre-production EUV scanner at Imec, with off-axis illumination provides resolution capability well below 22nm. In this paper we make a assessment of the EUV resist performance for 22nm LS and 28-26nm contacts on the NXE:3100. At 22nm feature sizes, pattern collapse and LER become the main resolution and process windows limiters. The application of FIRM~(TM) Extreme 10 rinse was found to be effective to improve the collapse margin and reduce LER on several resists. Using dipole illumination setting, we achieved 22nm LS at 13.5mJ/cm~2 with 3.1nm (3a) LER with wide processing latitudes. Several resists resolved down to 20nm LS. Champion resolution of 19nm LS was obtained in one resist at 20mJ/cm~2. Using quasar illumination, 28nm HP contact holes were obtained with LCDU value of 1.0nm (1σ) at <20mJ/cm~2, showing wide process latitudes. Printing 26nm HP contacts is feasible but requires further improvement in LCDU and contact shape circularity.