MULTI-LAYER WIRING BOARD AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A multi-layer wiring board and manufacturing method thereof have high reliability of electric connection between conducting layers by electroplating layer which is provided to a through-hole. CONSTITUTION: A plurality of conducting layers(1a) are piled by inserting resin insulation layers(2) thereby, and a through-hole(3) by which the conducting layer is exposed is formed on the insulation layer. An electroplating layer(4) for electric connection between the conducting layers is provided to the through-hole. The adjoining portion between inner side wall and bottom of the through-hole is formed in a concave curved surface whose radius is in the range of 20 and 100 micrometer. Accordingly, in the electroplating process, the equipotential surface in the through-hole is formed in a curved shape in the adjoining portion between inner side wall of the through-hole and the lower conducting layer, the current density is uniform. and the electroplating layer has a uniform thickness overall.