Assessment of EUV resist readiness for 32-nm hp manufacturing and extendibility study of EUV ADT using state-of-the-art resist

Extreme ultraviolet lithography (EUVL) is the most effective way to print sub-32 nm features. We have assessed EUVL resist readiness for 32 nm half-pitch (HP) manufacturing, presenting process feasibility data such as resolution, depth of focus (DOF), line edge roughness/line width roughness (LER/LWR), mask error enhancement factor (MEEF), resist collapse, critical dimension (CD) uniformity, post-exposure delay (PED) stability, and post-exposure bake (PEB) sensitivity. Using the alpha demo tool (ADT), a full field ASML EUV scanner, we demonstrate the feasibility of a k1 ~0.593 resist process for 32 nm HP line/space (L/S) patterning. Exposure latitude (EL) was 13% at best focus, and DOF was 160 nm at best dose using a 60 nm thick resist. By incorporating a spin-on underlayer, the process margin could be improved to 18.5% EL and 200 nm DOF. We also demonstrate ADT extendibility using a state-of-the-art EUV platform. A k1 ~0.556 resist process was demonstrated for 30 nm HP L/S patterns, providing a 13% EL, 160 nm DOF, and a common process window with isolated lines. 28 nm HP patterning for a k1 ~0.528 resist process could be feasible using a more advanced resist with improved DOF and resist collapse margin.