Double-sided wiring board, double sided wiring board manufacturing method, and multilayer wiring board

摘要

A single wiring layer is formed on each of both the roughened surfaces of a core substrate by a semiadditive method. The wiring layers formed on the surfaces of the core substrate are electrically connected through a through hole formed in the core substrate. The through hole is formed in the core substrate by laser machining. The through hole is filled up with conductive a plug. Both the surfaces of the core substrate are coated with solder resist layers, respectively, with predetermined terminal parts of the wiring layers exposed through openings formed in the solder resist layers. End surfaces of the conductive plug filling up the through holes, and the surfaces of the wiring layers are planarized by mechanical or chemical-mechanical polishing.