High NA (0.55) extreme ultraviolet (EUV) lithography brings the opportunity to simplify patterning processes for sub-2nm nodes by reducing mask counts/process cost and extending the minimum single expose pitch to sub-28nm, with ultimate resolution expected to be 16-18nm pitch. Our earlier work has highlighted the need for metal-oxide-resists for <24P scaling and for co-optimization between resist, underlayer, litho etch/processes to fully realize the benefits of High NA EUV (1). In this paper, we report progress at IBM Research towards down selection of photoresist, underlayer materials, develop/post-exposure processes and etch processes with High NA EUV toward maximizing lithographic performance at <24nm interconnect pitch applications. We also compare electrical yield performance with a BEOL Cu-damascene test vehicle to showcase best in class electrical yield results and correlate with defect metrology. These results will help understand pathways for yield step up and process maturity to accelerate High NA adoption in sub-2nm technology nodes.
Seshadri et al. (Thu,) studied this question.