Imaging roadmap for high-NA EUV: Paving the way to single-patterning of metal logic for future nodes

Abstract

High‑numerical‑aperture (high‑NA) extreme ultraviolet lithography (EUVL) is a key enabler for continued logic scaling beyond the 2 nm node. As metal pitches shrink, single‑exposure patterning becomes essential to reduce process complexity, improve variability, and control costs. However, standard EUV mask technology imposes limits on achievable resolution, depth‑of‑focus (DOF), stochastics, and printability for advanced logic features. This paper presents an imaging roadmap for high‑NA EUVL, focusing on mask technology enablers and enhancers that support single‑exposure metal patterning for future nodes from A14 onwards. We demonstrate improvements from mask tonality selection, novel low‑n absorber materials, sub‑resolution pattern design strategies, and mask‑scanner co‑optimization. Rigorous simulations and on-wafer validation experiments using the EXE:5000 scanner at the imec-ASML high-NA Lab validate the impact of these mask innovations on image contrast, depth-of-focus, exposure dose, and stochastic variability.