Constraint Graph-based PCB Legalization Considering Dense, Heterogeneous, Irregular-Shaped, and Any-oriented Components

In modern printed circuit board (PCB) designs, the increasing complexity poses more challenges for automatic placement. Existing PCB placement methods cannot handle complex constraints with heterogeneous, irregular-shaped, and any-oriented components for double-sided PCB designs well. This paper proposes the first constraint graph-based legalization approach for these constraints. We use a slicing technique to model a component more accurately with a set of rectangles instead of resorting to the naive bounding box approximation. Unlike the commonly used linear programming method for macro placement in integrated circuit (IC) designs, we employ a mixed integer linear programming (MILP) formulation to effectively expand the solution space for heterogeneous, irregular-shaped, and any-oriented components, particularly with high-density designs. Experimental results demonstrate the effectiveness and the robustness of our work.