Immersion lithography extension to sub-10 nm nodes with multiple patterning

This paper investigates the possibility of 193 nm immersion lithography extensions to sub-10 nm technology nodes using the patterning scheme of unidirectional (1D) grating lines and cuttings. Technological feasibility down to 5 nm nodes is examined with experimental data of self-aligned multiple patterning method (SAxP) and Litho-Etch (LE) cuttings. For the cutting by LE repetition, relationship between node definition and the repetition number n (LE(boolean AND)n) is discussed. Cost is evaluated for SADP, SAQP and SAOP to generate unidirectional grating formation, and the following LE(boolean AND)n cutting process. Finally, schemes of gridded cutting and trim are introduced, and found to be advantageous to keep the scaling merit of transistor cost at 7 and 5 nm technology nodes.