Restrictive design rules (RDRs) have been introduced as a simplified layout optimization method to better enable resolution enhancement techniques in ultra-deep submicron designs (16). In this paper, we study the technology migration problem for designs with strong RET-driven layout restrictions, i.e., RDR constraints, which require devices (gates) to be placed on a coarse pitch and in a single orientation. In particular, we study the legalization problem with on-pitch constraints for devices with an objective of minimum layout perturbation. The problem can be formulated as an integer linear programming (ILP) problem with a set of stringent integer constraints, and it can be approximated as a mixed integer linear programming (MILP) problem. Instead of using an MILP solver to solve it, we propose a two-stage method --- first the target on-pitch positions for gates are computed and second the original problem is relaxed to a linear programming problem. Library cell layouts designed in a technology with conventional ground rules have been migrated successfully to a technology with RDRs using our approach.

In this paper, we investigate routing restrictions that enable the generation of "correct by construction" layouts for Dark Field AltPSM. Existing routers produce designs in which coloring errors are numerous, and up to 15% of the pin locations in macros may cause unavoidable coloring errors. We identify routing restrictions which produce 100% phase-correct results, and quantify the impact on wire-lengths and via counts.