Copper Foil is the base copper thickness applied on outer and inner layers of the multilayer PCBs. The copper foil can be pre-bonded by the CCL or FCCL manufacturer to a base material core, or it can be pressed in a multilayer board, then to make copper conductor. The thicknesses of copper foil include 1/3oz, 1/2oz, 1oz, 1.5oz, 2oz and etc.