| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a highly reliable circuit board having excellent via connection stability.SOLUTION: A manufacturing method of a circuit board having high via connection stability can be provided by increasing the thickness of the surface layer of a plastic film layer, formed of a thermosetting resin not having a melting point that is a feature of a mask film, so that the mask film is brought into molten state by laser irradiation and collapsed by surface tension, and controlling the through hole diameter by a raised part formed because the cross section becomes thicker than the normal part. |
