| 摘要 |
PURPOSE:To reduce the manufacturing cost by a method wherein electroplating is applied to the end surfaces of interconnection layers in a through-hole to form conductor protrusions protruding toward the inside of the through-hole so as to be continuous with the respective interconnection layers and then through-hole plating is applied. CONSTITUTION:A multilayer interconnection board in which a through-hole 10 is formed is washed under a high pressure to eliminate cut trash and dust remaining in the hole 10. Then electrodes are lead out from interconnection conductors 4 and 5 of the inner layers and electroplating is applied. Conductor protrusions 8 and 9 are formed on the end surfaces of the interconnection conductor layers 4 and 5 on the wall surface of the through-hole 10. The protrusions 8 and 9 have circular shapes protruding along the wall surface of the through-hole 10. Thus, by forming the conductor protrusions on the end surfaces of the inner interconnection layers by electroplating after the through-hole is drilled, contact areas between the inner interconnection layers and a conductor layer formed by nonelectrolytic/electrolytic plating in a through-hole plating process afterwards can be increased so that the mechanical strength and the electrical connection at the connection parts of the through-hole plating layer and the inner interconnection conductor layers can be improved. |
