Printed wiring board having buildup layers and multilayer core substrate with double-sided board

Abstract

A printed wiring board includes: a multilayer core substrate including first and second insulation layers and a double-sided board between the first and second insulation layers. The core substrate has a cylindrical through-hole structure including a cylindrical conductor through the insulation layers and the board, a resin filler filling inside the cylindrical conductor and covering circuits covering the filler at the ends of the cylindrical conductor, respectively. The core substrate includes a conductive layer including a through-hole land around end of the structure such that the land is directly connected to the cylindrical conductor, the land includes a first electroless film, a first electrolytic film, a second electroless film and a second electrolytic film, and the cylindrical conductor includes the second electroless and electrolytic films such that the second electroless film is in contact with the side walls of the first electroless and electrolytic films.