| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board that is able to stably transmit a signal.SOLUTION: A wiring board A comprises: a first insulating layer 1 having a first area X where many through-holes 6 are formed with first array density and a second area Y where many through-holes 6 are formed with second array density lower than the first array density, and also having on its surface a conductive layer 3 for grounding or power supply; a second insulating layer 2 laid on the first insulating layer 1 and filling the through-holes 6; and a belt-like wiring conductor 4c for signals, which extends from above the first area X of the surface of the second insulating layer 2 to above the second area Y thereof so as to be counter to the conductive layer 3. In the wiring board A, many dummy through-holes H are arranged in parallel along the belt-like wiring conductor 4c, on both sides of a part counter to the belt-like wiring conductor 4c in the second area Y, and the second insulating layer 2 fills the dummy through-holes H. Thereby, the belt-like wiring conductor 4c from above the first area X to above the second area Y and the second insulating layer 2 between the belt-like wiring conductor 4c and the conductor layer 3 are made uniform in thickness. |
