2025 Volume E108.A Issue 3 Pages 517-524
In this paper, a routing problem for advanced chip designs is modeled as Gridless Gap Channel Routing (GGCR). GGCR is a routing problem to allocate variable-width trunks of nets to as fewer gaps as possible where a gap is defined horizontally between obstacles arranged regularly in the routing region. We propose Ceiling-and-Packing algorithm (CAP) for GGCR. CAP allocates the trunk of a net repeatedly so that each gap is filled as much as possible by adopting an appropriate order of allocation, and uses fewer gaps to complete the routing compared with conventional algorithms.