Multi-layer printed circuit board

摘要

A multi-layer printed circuit board has a through hole extending therein outside the mounting portion of a component mounted on the surface layer of the board. The component has a lead pad on the surface layer of a first printed circuit board and a modification pad on the surface layer between the through hole and the lead pad. The through hole extends through the first board to inside the mounting portion via a pattern of an internal wiring layer of the board. A second printed circuit board is joined to the first board at the internal layers of each to form a unitary integrated circuit board. Another through hole extends through the first and second boards inside the mounting portion of the integrated printed circuit board. The pattern and a selected wiring layer of the second board are thereby connected via the other through hole. Additional through holes extend through the second board and interconnect the layers of the second board. The additional through holes are positioned in areas devoid of the first-mentioned through hole.