| 摘要 |
PURPOSE:To easily confirm deviations of laminated layers and through holes of a multilayer printed circuit board by a continuity inspection. CONSTITUTION:An independent copper foil 2 having a clearance 1 of a value from a diameter of a drill to a value of (a diameter of a drill + tolerance) is provided on each of inner layers, through holes 4 are connected, and through holes 5 are formed at centers of the clearances 1 simultaneously with general through holes. Thus, when deviations of laminated layers and the holes become out of the tolerance, it can be easily discovered by conforming continuity between the holes 4 and 5. |
