Abstract: A printed circuit board includes a first electrically conductive circuit pattern, a substrate layer, an adhesive sheet, and a second electrically conductive circuit pattern, which are arranged in the above described order. The printed circuit board includes a single layer electrically conductive circuit area. The adhesive sheet defines a first opening spatially corresponding to the single layer electrically conductive circuit area. The adhesive sheet includes a first inner sidewall surrounding the first opening. The second electrically conductive circuit pattern defines a second opening spatially corresponding to the single layer electrically conductive circuit area. The second electrically conductive circuit pattern includes a second inner sidewall surrounding the second opening. The first inner sidewall and the second inner sidewall are not completely coplanar.

Abstract: A method for manufacturing a multilayer FPCB includes certain steps. A first printed circuit substrate is provided, the first printed circuit substrate includes a first copper layer and a first protective film, the film defining a first opening. A second printed circuit substrate is provided, this substrate includes a second copper layer and a second protective film. The second protective film defines a second opening. The first printed circuit substrate is laminated together with the second printed circuit substrate by an adhesive sheet. The adhesive sheet defines a third opening in communication with and aligned with the first opening and the second opening. The first copper layer is then etched to form a first outer wiring layer and the third copper layer is also etched to form a second outer wiring layer, thereby obtaining a multilayer FPCB.