Simultaneous Two-Dimensional Cell Layout Compaction Using MILP with ASTRAN

This paper describes a technique to compact cell layouts efficiently using Mixed-Integer Linear Programming. By using binary variables we were able not only to model the conditional design rules, which apply to technology nodes down to 65nm, but also to compact layouts in the two-dimensions simultaneously. This technique was applied to a transistor network layout synthesis tool called ASTRAN which is being used to generate on-demand cells with unrestricted transistor network structure. We demonstrate in this paper that our technique is able to generate dense cell layouts, competitive with manually designed cells.