| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit board which is prevented from deteriorating in high-frequency characteristics, wherein an insulating film is kept free from bulging or delamination, and a metal film is protected against cracking. SOLUTION: A circuit board 10 is equipped with circuit layers 12 laminated on a board 11. Each circuit layer 12 is equipped with a titanium thin film 13, a palladium thin film 14, a gold plating film 15, a via plating film 16, a molybdenum film 17 which covers the surface of the gold plating film 15 and the via plating film 16, and a polyimide insulating film 18 which covers the molybdenum film 17 and the side of the gold plating film 15. The molybdenum film 17 is comparatively excellent in adhesion to the polyimide insulating film 18, so that the polyimide insulating film 18 is kept free from bulging or delamination. Cracking hardly occurs in the molybdenum film 17 when polyimide precursor is cured, and as the molybdenum film 17 is not ferromagnetic, it hardly deteriorates the circuit board in high-frequency characteristics. |
