A multilayer printed circuit board and manufacturing method therefor

摘要

A laminate of wiring layers are stacked up on one side of a copper clad glass-epoxy substrate by alternately depositing photosensitive resin layers and electrolessly plated copper layers. The copper layer on the one side of the copper clad substrate is used as a first level wiring layer. Interconnection of the wiring layers are made by vias in the photosensitive resin layers. The copper layer on the other side of the substrate is used as a power plane. Interconnection between the power plane and power supply pads or lands in the outermost wiring layer is made by plated through holes which extend through the substrate. Thus the photoprocessed vias are used for interconnection of signal conductors in the wiring layers and the plated through holes are used for power connections. This minimizes the use of relatively large, mechanically drilled through holes to thereby provide higher circuit density. The laminate of the wiring layers may be provided on both sides of the substrate. In this modification, the copper layer on the other side of the copper clad substrate may be used as an additional wiring layer, not as a power plane, and the power conductors are formed in the outermost copper layers, which are interconnected by through holes.