METHOD OF MANUFACTURING FLEXIBLE PRINTED BOARD JUNCTION

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a flexible printed board junction, for obtaining the flexible printed board junction excellent in bonding strength regardless of the hardness or surface roughness of a metal pad part in a flexible printed board to be bonded.SOLUTION: The method of manufacturing the flexible printed board function includes a flexible printed board preparation process of preparing a first flexible printed board including a connection area provided with a wiring part and a metal pad part formed on the wiring part with gold as a main component and a second flexible printed board, a crystal coarsening process of executing crystal coarsening processing of coarsening the size of a metal crystal included in at least one of the metal pad parts, and a diffusion bonding process of closely attaching the metal pad parts and diffusion-bonding both by ultrasonic bonding after the crystal coarsening process.