Nec Corporation

Seiji Furui

Kiminori Ishido

Ryo Maniwa

Keisuke Okada

A multilayered board is formed by applying a photosensitive insulating resin layer on a laminated plate on which via holes and a circuit pattern are formed, followed by the formation of photoviaholes through the photoprinting method, plating and etching. Then, the multilayered board is adhered to another multilayered board prepared in the same manner through a prepreg layer and a conductive paste while applying heat and pressure to give a multilayer printed wiring board. According to this method, electrical connections between the conductive layer of the upper-most layer and the inner conductive layers, between the inner conductive layers, and between the lower-most conductive layer and the inner conductive layers can be achieved through the photoviaholes and the conductive paste. Therefore, it is not necessary to form through-holes for the electrical connection therebetween. The multilayer printed wiring boards can be substantially improved in the number of layers and wiring density thereof.

Growing community of inventors

Tokyo, Japan

Seiji Furui