“…There are two main strategies to solve the global routing problem: three-dimensional (3D) global routing and two-dimensional (2D) global routing followed by layer assignment. A 3D global router transforms the global tiles of all routing layers into a 3D global routing graph and applies maze routing or an integer linear programming (ILP) formulation to directly derive 3D routing paths [13,16]. Due to the increasing number of routing layers and chip size, the extremely high routing complexity can result in prohibitively large runtime cost.…”