Patent ID: 7765692

Claim:
A manufacturing method of a printed wiring board in which a conductor pattern is formed on an upper face of an insulating layer and a pad for external connection is formed on a lower face of the insulating layer, and said conductor pattern and the pad for external connection are electrically connected to each other by a hole for conductivity; the manufacturing method being characterized in that: an upper face copper foil and a lower face copper foil are first respectively stuck to the upper and lower faces of the insulating layer; an opening hole is next formed by removing a portion corresponding to a forming portion of the hole for conductivity in said upper face copper foil by etching; the hole for conductivity is next formed in the insulating layer exposed from the opening hole of said upper face copper foil, and a bottom portion of the hole for conductivity is set to reach said lower face copper foil; a chemical plating film is next formed in an inner wall of the hole for conductivity; an electric plating film for continuously covering the inner wall and the bottom portion of the hole for conductivity is next formed within the hole for conductivity; a conductor pattern electrically connected to said hole for conductivity is next formed from the upper face copper foil by etching said upper face copper foil and the lower face copper foil, and a pad for external connection for closing an opening portion of said hole for conductivity is formed from said lower face copper foil.