| 摘要 |
PROBLEM TO BE SOLVED: To raise the reliability of connection of wire bonding by forming a recession where a first circuit pattern is exposed, in such a way as to be surrounded by an insulating layer at a part to be wire-bonded on the first circuit pattern. SOLUTION: First of all, inner conductor layers 11 are formed on both surfaces of an insulating board 10, and on them inner-layer circuit patterns 11a are formed. And surface treatment of the surfaces of the inner-layer circuit patterns 11a (first circuit patterns) is performed. After that, insulating layers 12 are formed on the whole surfaces including the inner-layer circuit patterns 11a, and then through holes 13 are formed. And outer conductor layers 14 to be second layers are formed by plating. On this occasion, it is favorable that the surfaces of the insulating layers 12 should be coarsened. After that, outer- layer circuit patterns 14a (second circuit patterns) are formed. At the time of forming these patterns, the outer conductor layers 14 and the insulating layers 12 are removed. Along with it, the inner-layer circuit patterns 11a are exposed, and a recession 15 surrounded by the insulating layers 12 is formed at parts to be wire-bonded. |
