Multilayer printed circuit board

摘要

A multilayer printed circuit board comprises plural insulating layers integrated into one body, and internal wiring conductor layers located on the internal insulating layers, characterized in that conductor paths in each internal conductor layer are locally separated from the insulating layer by a cavity or porous layer provided at the boundaries between the path and insulating layer adjacent thereto. At least one insulating layer between internal conductor layers may be provided with a layered space or porous layer therein.