Evaluation of Electric Reliability for Flexible Printed Circuit Boards with Anisotropic Conductive Film by AC Impedance Method

The AC Impedance Method is well known as a method for analyzing the reaction mechanism in the process of the occurrence and growth of ionic migration on the surface of printed circuit boards. We applied this method to fine-pitch FPC boards on which were mounted ICs by ACF. The various production conditions of this sample were changed, and the AC Impedance Method was applied in a high voltage environment under high temperature and high humidity. The results clearly showed that the prediction of electric reliability is possible.