| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a flexible wiring board which has good productivity even when a via hole has a small diameter and which has excellent reliability in connection between layers.SOLUTION: A flexible wiring board manufacturing method comprises: providing alkali soluble and uncured adhesive resin layers (21a, 21b) on surfaces of copper foils (12a, 12b) of a core substrate (10), and copper foils (22a, 22b) on surfaces of the uncured adhesive resin layers, respectively; forming openings by removing parts of the copper foils (22a, 22b); and removing the uncured adhesive resin layer (21a, 21b) exposed in the openings by etching using an alkaline solution to form via holes which reach the copper foils (12a, 12b), respectively. In the etching, the alkaline solution is sprayed from the copper foils (22a, 22b) side during a processing time 0.1-0.6 times longer than a time required until removing the uncured adhesive resin layers (21a, 21b) and subsequently water washing is performed from the copper foils (22a, 22b) side by a spray at a water pressure of not less than 0.10 MPa and not more than 1.0 MPa. |
