| 摘要 |
PURPOSE:To avoid the degradation of a wiring pace factor caused by a via-hole neck by a method wherein a plurality of non-through via-holes are provided vertically to both the surface and rear of a board as the via-holes connecting between the signal layers of the board and the non-through via-holes are brought into contact with one inner layer signal line provided in the middle of the surface and rear signal layers at the different positions. CONSTITUTION:In addition to a vertical through via-hole 1, two non-through via-holes 2 and 3 are provided in board 6 and the tips of the two non-through via-holes 2 and 3 are connected to each other with an inner layer signal line 4. Therefore, although a surface layer signal line 5 can not be provided on the position where the through via-hole 1 exists, the surface layer signal lines 5 can be provided at the positions where the via-holes 2 and 3 exist by employing the non-through via-holes 2 and 3. As the vertical via-hole is employed, the degradation of the position accuracy of the via-hole and breakage of a drill can be avoided and, as the non-through via-holes are employed, the surface signal lines can be provided at the same positions as the via-holes on the non-through sides. With this constitution, the degradation of the wiring space factor caused by a via-hole neck can be avoided. |
