| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer flexible printed circuit board, capable of mounting narrow pitch CSP and in which an outer layer circuit and an inner layer circuit have flexible cables that can form fine circuits, and to provide a multilayer circuit base material used for the method. SOLUTION: A double-sided copper clad laminate is prepared, and copper plated layers on an outer layer side and an inner layer side, which have openings for continuity holes on the outer layer side and the inner layer side of the copper clad laminate, are formed by an electrolytic copper plating method in such a way that thickness of the copper plated layer on the inner layer side becomes two or three times as much as the copper plated layer on the outer layer side. A cover layer is formed on the copper plated layer on the inner layer side and is set to be a laminate base material 12 from an outer layer. Alternatively, a wiring board having at least one wiring layer is prepared and a multilayer circuit base material is formed by laminating the laminate base material. Collective laser processing is performed through first and second openings of the multilayer circuit base material and the continuity holes 16 and 17 are formed. A conducting processing and electrolytic plating are performed so as to form via holes 16b and 17b. COPYRIGHT: (C)2011,JPO&INPIT |
