Semi-damascene Integration of a 2-layer MOL VHV Scaling Booster to Enable 4-track Standard Cells

Abstract

A new cell routing architecture called vertical-horizontal-vertical (VHV) which requires a two-level (2L) middle-of-line (MOL) scheme has been proposed as a scaling booster to enable 4-track (4T) standard cell (SDC) templates for beyond the 2 nm technology node. In this work, we demonstrate an innovative integration strategy using the semi-damascene technique to implement the 4T VHV, enabling the precise definition of a tight boundary between SDC's which requires two vias with zero-line extension facing each other and a tip-to-tip (T2T) at the underlaying layer, all at a distance of 'one CD' of the top layer. As a result, we obtained an average via CD = 10.5 nm with a resistance of 24 Omega, and a T2T = 8.9 nm. Both vias and T2T were self-aligned to the 18 nm pitch layer above.