US Patent 7642571 Substrate core

A substrate including a first patterned metallic layer, a second patterned metallic layer and an insulator is provided. One side of the first patterned metallic layer is connected to a corresponding side of the second patterned metallic layer. The first patterned metallic layer and the second patterned metallic layer are formed as a whole. The insulator fills the gaps in the first patterned metallic layer and the gaps in the second patterned metallic layer.