| 摘要 |
PURPOSE:To inspect an inner layer positional accuracy in short time, to improve productivity and to save materials by disposing a conductor pattern formed on an inner layer or the inner layer and an outer layer at the same positions of the layers, and providing a through hole passing a conductor pattern. CONSTITUTION:Conductor patterns 2 disposed at the same positions of outer and inner layers of a multilayer printed circuit board 1 are provided, and a through hole 3 passing these circular patterns 2 are opened simultaneously with a component mounting hole by an NC drill. Then, the patterns 2 formed with the hole 3 are transmitted by an X-ray to inspect the positional accuracy of the inner layers. If the positions of the inner layers are normal, the patterns 2 are transmitted in the concentric circle with the hole 3. If they are deviated, multiple circles are transmitted, its deviated amount from the hole 3 is measured to detect its malfunction. |
