Embodiments of the invention include methods, systems, and computer program products for checking metal coverage in a laminate structure. Aspects of the invention include receiving, by a processor, metal shadowing rules and a semiconductor package design comprising a plurality of laminate layers, a plurality of metal power shapes, and a plurality of signal lines. Each metal power shape is mapped to one or more cells in a two-dimensional array. The processor determines, for each signal line in the semiconductor package design, whether the metal power shapes satisfy the metal shadowing rules. The processor displays a list of signal lines that do not satisfy the metal shadowing rules.