Definition

Laminate is the fully cured (C-stage) base material of a PCB, consisting of reinforcement (typically fiberglass) and resin, clad with copper foil on one or both sides. Laminates are specified by material type (FR-4, high-frequency, polyimide), thickness, copper weight, and electrical properties (Dk, Df, Tg). In multilayer PCBs, laminates form the cores that are bonded together with prepreg during lamination. The laminate material system must be compatible across all layers.