| 摘要 |
PURPOSE:To prevent short circuit caused by migration by forming a conductive part in a through hole by copper electrolytic plating and forming a conductive metal thin film which generates relatively less migration than copper by electrolytic plating so as to cover circuit surface. CONSTITUTION:A copper plated laminated plate, whose base insulating material layer 7 is bonded with a composite copper foil provided with a migration preventing metal thin film by lamination, is provided, and after making a through hole 12, a migration preventing metal thin film 10 is formed on the through hole inner wall, where the insulating layer cross section is exposed, by electroless plating. Then, copper plating is performed by the electroless plating in order to thicken the film to the normal through hole level and, a circuit is formed by the normal etching process. Therefore, when the circuit formation is completed, the migration preventing metal thin film previously formed on the copper foil is formed on the side of the circuit bottom and the whole circuit surface made of the copper foil 11 is coated by the migration preventing metal thin film on the copper foil exposed on the side of the circuit bottom and a same metal thin film formed by plating. |
