PRINTED WIRING BOARD AND METHOD FOR MANUFACTURING THE SAME

摘要

PURPOSE: A printed wiring board and method for manufacturing the same are provided to realize high-density packaging and particularly to a printed wiring board having an odd number of conductive layers, a printed wiring board having build-up layers formed by using the additive method and the like, a method of forming interconnecting through holes for electrically connecting conductive layers and narrowing the pitch between solder balls for external connection and the interconnecting through holes. CONSTITUTION: In a printed wiring board, an odd number(n) of conductive layers(11-13) and insulating layers(21-23) are alternately laminated upon another. The first conductive layer(11) is constituted as a parts connecting layer and the n-th conductive layer(13) is constituted as an external connecting layer which is connected to external connecting terminals(7). The second to(n-1)-th conductive layers(12) are constituted as current transmitting layers for transmitting internal currents. The surface of the n-th conductive layer(13) is coated with the outermost n-th insulating layer(23) in a state where the external connecting terminals(7) are exposed on the surface. It is preferable to constitute the initial insulating layers of a glass-cloth reinforced prepreg and the external insulating layers of a resin.