| 摘要 |
PROBLEM TO BE SOLVED: To improve wiring efficiency of a buildup multilayer printed wiring board. SOLUTION: After circuit patterns 2a, 2b in insulating layers 4a, 4b and conductive bumps 3a, 3b are formed by etching, the insulating layers 4a, 4b are so formed that surfaces of the conductive bumps 3a, 3b are exposed. |
