| 摘要 |
PROBLEM TO BE SOLVED: To increase flexibility in design of the diameter of a through-hole by boring a hole at a prescribed position of a conductor layer of a laminate, sandblasting an insulating resin layer appearing from this hole and forming a through-hole forming hole in the insulating resin layer. SOLUTION: An insulating resin layer 2 and conductor layers 3 are laminated in a laminate 1, and a resin layer 4 composed of a photosensitive resin structure, etc., is formed on the surfaces of the conductor layers 3. Desired through-hole forming portions on a conductor layer 3 side is masked to expose the resin layer 4. After that, the non-exposed part is developed and removed, and the exposed part is formed as an etching resist 5. Furthermore, an insulating resin layer 2 appearing from the through-hole forming holes 6 of the conductor layer 3 is sandblasted, and through-hole forming holes 7 up to the conductor layer 3 of a lower layer are formed in the resin layer 2. |
