Channel density reduction by routing over the cells (Conference)

摘要

[[abstract]]An approach for reducing the density of a channel by routing some nets (or subnets) over the cells (i.e. outside the channel) is proposed. Previous research assumed that the more nets being routed over the cells, the greater the reduction in the channel density. It is shown that only the removal of critical nets contributes to the reduction in the channel density. The channel is divided into zones where each zone has a zone density and the removal of any net from a zone will reduce its density by one. In order to reduce the channel density, only certain critical zones need to have their nets routed over the cells. A bipartite graph is used to represent the relationship between nets and zones. The problem is transformed into a constrained covering problem and formulated as an integer linear programming problem. In comparison with previous research, this approach reduces more channel densities while using fewer tracks over the cells.