| 摘要 |
PROBLEM TO BE SOLVED: To raise connection reliability between upper and lower conductor circuits and realize reduction in a cost of a connection means between upper and lower conductor circuits by raising dimensional stability in a manufacturing process, by preventing generation of bending, snapping and wrong sizes in a manufacturing process. SOLUTION: A conductor circuit formation copper foil 23 is formed on a projection formation copper layer 21 via an etching barrier layer 22 formed of another metal, projections 25 are formed by selectively etching the projection formation copper layer 21 by means of etchant which does not attack the etching barrier layer 22, the etching barrier layer 22 is removed by etchant which does not attack the copper foil 23 forming a conductor circuit by using the projections 25 as masks, and a layer insulation film 27 is formed on the surface on the projection formation side of the copper foil 23 as an interlayer connection means where the projections 25 are connected to a conductor circuit. |
