| 摘要 |
PURPOSE: To form a multilayer printed circuit board with accuracy in board thickness, regardless of the rate of a residual inner copper foil, by using double- layer copper foil made of an outer-circuit copper layer with a given thickness and a metallic layer to be removed after lamination. CONSTITUTION: An aqueous undercoating material 3 is applied on an inner-layer circuit 1 thick enough to coat an inner-layer circuit 2 at the same time. A double-layer copper foil 5 made of an outer-circuit copper layer 1 to 50μm thick and a metallic layer 10 to 20μm thick to be removed after laminating, is laminated with an overall thickness of 11 to 250μm using a thermosetting insulating adhesive. Then, the undercoating material 3 and the thermosetting adhesive 4 on the copper foil are molded at the same time integrally in a heat curing step. After that, the outer carrier part, where an outer-layer circuit is not formed in the double-layer copper foil 5, is removed to complete a multilayer printed circuit board with an outer-layer circuit. |
