| 摘要 |
PROBLEM TO BE SOLVED: To provide a double-sided flexible printed circuit board (FPC), a multilayer flexible circuit board, and a method for manufacturing them, which are high in the connection reliability, suitable for the microfabrication of wiring layers, and excellent in the productivity. SOLUTION: The FPC includes an insulation layer 2, circuit layers 3, 4 laminated on the upper and lower sides of the insulation layer 2, and an interlayer connection to connect between the circuit layers 3, 4. The interlayer connection consists of a mortar shape conductor press fit hole 5 penetrating the insulation layer 2 and the upper and lower wiring layers 3, 4 are opened/enlarged toward the wiring layer 3 side in one side. The conductor 6 filled/press fitted to the press fit hole 5 leaving no space between is joined to the one side of the upper circuit layer 3 deformed into the mortar shape of the conductor press fit hole 5, and it is protruded from the lower circuit layer 4 in another side and a part of the surface is coated/bonded. Consequently, the contact area increases in the circuit layers 3, 4 and the conductor 6 filled in the conductor press fit hole 5, and the adhesion strength of the wiring layers 3, 4 and the conductor 6 is secured sufficiently to obtain high connection reliability of the interlayer connection portion. COPYRIGHT: (C)2007,JPO&INPIT |
