| 摘要 |
PROBLEM TO BE SOLVED: To improve the close contact between an inner layer circuit and an insulating resin layer by a method wherein an insulating resin layer is formed on the inner layer circuit, and when an outer layer circuit is formed thereon, a continuous rugged surface of specific height is formed on the surface of the inner layer circuit. SOLUTION: The surface 2a of the inner layer circuit 2 formed on both faces of a glass epoxy copper-clad board 1 is micro-etched by a treatment solution which is formed by adding a chelating agent to an organic acid. As a result, about 4 to 450,000/mm<2> continued rugged conical of about 1.5 to 5.0μm in height and diameter of bottom part are formed on the surface 2a. Consequently, as the close contact between an insulating resin layer and the inner layer circuit is improved by an anchor effect, a highly viscous insulating resin layer can be used. Accordingly, an insulating resin layer, having the thickness more than required, and working hours can be cut down. |
