摘要 |
<p>A flexible circuit board for mounting IC has conductor bumps on the rear surface, and they penetrate the flexible circuit 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 easily connected to the bumps of the circuit board by a thermal or ultrasonic bonding method. When such bumps or protrusions for bonding to IC pads are provided on the flexible circuit board, tiny holes are preferably formed in the insulating substrate by excimer laser means. The bumps are formed by plating means such as soldering or by a suitable treatment for filling the holes with an electrically conductive material. Further, the bumps should desirably be formed in a semi-spherical shape by the reflow treatment.</p> |