| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent a short circuit from occurring between power supply solid layers even if foreign particles are attached in an exposure process by a method wherein an insulating layer is formed on an insulating board where a wiring is formed, and a via is provided so as to connect two wiring layers which are formed separating vertically from each other through the intermediary of the insulating layer. SOLUTION: A wiring resist 2 is applied to a base material 1, a wiring 3 is formed, insulating resist 4 is applied to the base material 1 twice, exposed, and developed to form a via 5a in the insulating layer. Furthermore, insulating layer resist 4 is applied, exposed, and developed to form a via 5b which communicates with the via 5a. Thereafter, the insulating resin layer 4 is thermally set, roughened, and given catalyst, wiring resist 6 is applied, electroless copper plating is carried out for the formation of a wiring 7, and the wiring 7 is polished. By this setup, a via 5 which electrically connects the lower wiring 3 and the upper wiring 7 together is formed. |
