| 摘要 |
PURPOSE:To improve connection reliability in a hole by selectively thickening only a conductor layer in the small-diameter bias hole by plating for a multilayer interconnection board which has the small-diameter bias holes which selectively connect a plurality of conductor circuits. CONSTITUTION:On the necessary areas on a wiring board, holes 1 and 2 for blind bias holes are provided and electroless thick plating is performed on thew hole wiring board including the inside of the holes for 10mum. Then, photosensitive dry films are laminated on the both sides of the wiring plate and patterns are formed on the parts where the patterns are overlapped with the holes so as to form holes whose diameters are 0.06mm smaller than the hole diameters. Electroplating is performed through the dry film parts formed by such method allowing the hole diameters slightly smaller than the holes formed and copper layers 9 which have the thickness of 80mum are formed only in the holes. The multi-layer wiring board manufactured in such manner does not allow crack on the blind bias holes 1 and 2 up to 300 cycles. |
