| 摘要 |
PROBLEM TO BE SOLVED: To improve the alignment accuracy between the photo-vias and external-layer pattern of a built-up multilayered printed wiring board. SOLUTION: A built-up multilayered printed wiring board 10 is constituted by forming an insulating layer 17 on a printed wiring board having reference holes and an internal-layer pattern 13 and an external-layer pattern 20 on the insulating layer 17. Photo-vias 18a, 18b, 18c and a photo-via 21 for positioning are formed through the insulating layer 7 on the basis of the reference holes and the external-layer pattern 20 is formed on the basis of the photo-via 21 for positioning. |
