Abstract: This invention relates to a printed wiring board having two electrically conductive circuit layers on an insulating laminate. The insulating laminate includes a first insulating layer having a thickness of 0.01 to 0.5 mm, and metal foils are provided on both sides of the first insulating layer. Metal foil circuit layers of predetermined patterns are formed by printing and etching the metal foils. Thereafter, through holes are formed in the first insulating layer across the facing metal foil circuit layers, and then electrically conductive members are applied over the through holes and the metal foil circuit layers at their ends. After that, a second insulating layer is attached onto one of the sides of the first insulating layer on which the connected metal foil circuit layers are provided.

Abstract: This invention relates to a process of producing a printed wiring board having first and second electrically conductive circuit layers provided on an insulating laminate. The insulating laminate includes a first insulating layer having metal foils provided on both sides thereof and a second insulating layer which is attached to one of the sides of the first insulating layer so as to place one of the electrically conductive circuit layers between the first and second insulating layers. The first electrically conductive circuit layer is formed in a predetermined pattern by printing and etching one of the metal foils. Then, connecting through-holes are formed in the first insulating layer across the first electrically conductive circuit layer and the remaining metal foil. The second insulating layer is attached onto the first insulating layer so that the first electrically conductive circuit layer is covered with the second insulating layer.