Patent ID: 6890449

Claim:
A method of manufacturing a printed circuit board comprising: providing a substrate having front and back faces, said substrate comprising fibers and a thermosetting resin; forming a through-hole in a releasing film wherein a thickness of said releasing film around edges of the through-hole is thicker than all remaining portions of said releasing film, forming a through-hole in the substrate, the through-hole in the substrate having a larger diameter than the through-hole in the releasing film; laminating the substrate having a through-hole with a first said releasing film on the front face of the substrate and a second said releasing film on the back face of the substrate so that the through-hole in each releasing film is in axial alignment with the through-hole in the substrate; filling the through-hole in the substrate and in the releasing films with conductive paste; then removing said releasing films from said substrate; then locating metal foils on the front and back faces of said substrate after removing said releasing films and making said metal foils integral with said substrate by heat pressing; and patterning said metal foils.