Design technology co-optimization (DTCO) study on self-aligned-via (SAV) with Lamella DSA for sub-7 nm technology

In this paper, we present a design technology co-optimization (DTCO) flow to pattern self-aligned via (SAV) using two masks with grapho-epitaxy of lamella BCP and 193i for sub-7nm design. We show that it is necessary to consider both metal and via layers at the same time in creating design rules with process variations. Due to lamella DSA’s own characteristics, it can be easily applied in dense memory or SRAM applications for SAV patterning using traditional single-material metal hard mask. However, to achieve two-mask SAV solution for logic applications, we need to apply alternating hard mask in metal to cut lamella DSA patterns without compromising the technology scaling.