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 FIRMTM 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/cm2 with 3.1nm (3σ) LER with wide processing latitudes. Several resists resolved down to 20nm LS. Champion resolution of 19nm LS was obtained in one resist at 20mJ/cm2. Using quasar illumination, 28nm HP contact holes were obtained with LCDU value of 1.0nm (1σ) at 2, showing wide process latitudes. Printing 26nm HP contacts is feasible but requires further improvement in LCDU and contact shape circularity.