BCA Channel Routing to Minimize Wirelength for Generalized Channel Problem

Routing has a crucial impact on chip design [1]. In this paper, a BCA (Below-Cross-Above) routing, especially for critical routing layers, is proposed. It is assumed that horizontal routing capacity is tight and that all pins of a net need to be connected by a Single Trunk Steiner Tree. Our proposed algorithm is a greedy algorithm based on a well-known Left-Edge algorithm. The track assignment of nets is determined iteratively by taking net priority into account to reduce the vertical length while keeping the required number of tracks as small as possible. In experiments, it is confirmed that the vertical wirelength is reduced by around 40% compared with the track assignment by Left Edge algorithm.