| 摘要 |
Provided is a technique for obtaining a multi-layer substrate comprising a via conductor with high dimensional precision. A multi-layer substrate (2) includes a layered body (3) formed by layering a plurality of insulating layers (3a, 3b), and the multi-layer substrate is provided, on the uppermost insulating layer (3a) of the layered body (3), with a via hole (4a) formed by passing through the insulating layer (3a), and a via conductor (5a) formed by filling in this via hole (4a) with a conductive paste. The via hole (4a) is formed so that, with respect to a lower-end position, an upper-end position, and an intermediate position between the lower-end position and the upper-end position, the degree of widening of the diameter from the intermediate position to the upper-end position is greater than that from the lower-end position to the intermediate position. By forming the via hole (4a) in this way, if the via hole (4a) is filled with the conductive paste from the opening on the smaller-diameter side, the dimensional precision of the via conductor (5a) is improved because exudation of the conductive paste from the opening on the larger-diameter side is prevented. |
