| 摘要 |
PROBLEM TO BE SOLVED: To lessen a contact resistance between a non-through connection hole and internal layer circuits and also to reduce the continuity failure between the internal layer circuits. SOLUTION: A land part 2a, whose diameter is R1 , is formed on a first internal layer circuit 2 formed on the copper-clad laminated board on one side of copper-clad laminated boards. A second internal layer circuit 9 is formed with an insulating resin layer 5 between the circuits 2 and 9 and a land part 9a, which is bored with a hole 9b of a diameter of R3 and has the diameter of R1 , is formed on this circuit 9. A semi-non-through hole part 131, whose diameter is R2 , and a non-through hole part 132, whose diameter is R3 , are formed by a laser of the diameter R2 , the relation being R1 >R2 >R3 . |
