| 摘要 |
PROBLEM TO BE SOLVED: To develop photosensitive resin layers formed on both surfaces of a substrate at the same time, with the substrate kept in an upright state, by spraying developer from both sides of the substrate at the same time, for preventing the occurrence of undeveloped area. SOLUTION: In manufacturing a multi-layer printed wiring substrate, when an inter-layer insulating material layer comprising a viahole opening of a photosensitive resin layer on both surfaces of the wiring substrate, the multi-layer printed wiring substrate is kept in an upright state, a development process is performed by spraying a developer to the both surfaces of the photosensitive resin layer at the same time. Thereby, with undeveloped area left, the photosensitive resin layers formed on the both surfaces of the multi-layer printed wiring substrate are developed uniformly at the same time. |
