| 摘要 |
PROBLEM TO BE SOLVED: To produce a fine high density build-up wiring board by making a wiring groove in an insulating resin layer formed on a basic material and adsorbing metal colloid, forming a metal film using a conductive layer as cathode and polishing the metal film and then removing the metal film and the metal colloid except the inside of the groove. SOLUTION: A coating of photosensitive varnish for forming an interlayer insulating resin layer 5 is provided on a wiring board comprising a basic material 1, i.e., a copper clad polyimide laminated board, and a first wiring layer 2. It is then dried and via holes are made in the resin before being hardened through polymerization. Subsequently, an interlayer insulating resin layer 7 is formed. Surface of the resin layers 5, 7 is then roughened by making irregularities at high density in order to facilitate adsorption of colloid in subsequent steps and immersed into a cationic surfactant solution thus adsorbing cations to the surface of the board. Finally, it is immersed into an alkaline carbonate solution in order to reduce the adsorbed colloid thus forming a conductive layer. According to the method, wiring and vias 10 can be embedded flatly in a resin. |
