Layer assignment problem for three-layer routing

The layer assignment problem for interconnect is the problem of determining which layers should be used for wiring the signal nets so that the number of vias is minimized. The problem is often referred to as the via minimization problem. The problem is considered for three-layer routing, concentrating on one version called the constrained via minimization (CVM3) problem. It is shown that the CVM3 problem is NP-complete and a heuristic algorithm is proposed. The experimental results show that the proposed algorithm is efficient and generates fairly good solutions