Gridless Gap Channel Routing to Minimize Wirelength

Abstract

Gridless Gap Channel Routing (GGCR) is a routing problem defined in a critical routing layer in an advanced chip where a single horizontal trunk Steiner tree connects each net. The trunk widths are not unique, and trunks are allocated to partitioned routing areas, called gaps, without overlap. This paper proposes criticality-based ceiling and packing (CCAP) for GGCR to shorten the wirelength. CCAP routes a net with a smaller wirelength as much as possible by considering the congestion of gaps and the criticality of nets in terms of wirelength.