METHOD OF PRODUCING A FLEXIBLE CIRCUIT BOARD FOR MOUNTING IC's

摘要

The board has conductor bumps on the rear surface, and they penetrate the board to connect a circuit wiring pattern. The surfaces of the bumps can be coated with a bonding metal depending on the structure of the bumps. Bare IC chips are connected to the bumps of the circuit board by a thermal or ultrasonic bonding method. When bumps or protrusions for bonding to IC pads are provided on the flexible circuit board, tiny holes are pref. formed in the insulating substrate by an excimer laser. The bumps are formed by plating, e.g. soldering, or by a suitable treatment for filling the holes with an electrically conductive material. The bumps should desirably be formed in semi-spherical shape by the reflow treatment. @(22pp Dwg.No.1/11)@.