| abstract |
A method for manufacturing a thinner circuit board capable of realizing fine wiring of a wiring layer. An insulating base material having a second main surface 20b opposite to a first main surface 20a, wherein one or more prepregs and a resin composition layer are integrally cured, the first main surface A method of manufacturing a circuit board 10 having a first wiring layer 32 provided on a second wiring layer 34 and a second wiring layer 34 provided on a second main surface, wherein the step (A) includes an organic support and an organic support. A step of preparing a structure made of an insulating base material bonded to the surface and a conductive foil bonded to the second main surface; and step (B) laser irradiation from the first main surface side for insulation. Forming a via hole 22 that penetrates the conductive base material to expose a part of the conductor foil, a step (C) a roughening treatment, a step (D) a step of forming a conductor layer, and a step (E) Forming a first wiring layer and a second wiring layer. [Selection] Figure 1 |