| 摘要 |
PURPOSE:To eliminate a 'halo' or a 'pinkring' due to dissolution of copper oxide by aqueous acidic solution from copper oxide by chemically oxidizing the copper foil of an inner layer plate formed with a printed circuit network to form a brown or black copper oxide, and then treating it in a reducing gas presence atmosphere. CONSTITUTION:A copper foil as an inner layer plate formed with a printed circuit network for an inner layer used as an intermediate layer is chemically oxidized to form a black or brown copper oxide, treated in vapor state dry and reducing gas presence atmosphere, or a multilayer plate obtained by laminating multiple layers to be molded is opened and reduced in vapor state. In this case, as the reducing gas hydrogen, carbon monoxide or their mixture gas is used. A multilayer printed board manufactured in this manner can greatly reduce or entirely eliminate a 'halo' tending to cause a malfunction such as an electric short-circuit due to dissolution of brown or black copper oxide in plating solution in a through hole plating step for electrically conducting between printed circuits of the multilayer board. |
