Relationship between curing conditions and interconnect properties of flexible printed circuit/glass substrate joints using anisotropic conductive films

Abstract

This paper investigates the mechanical and electrical properties of anisotropic conductive film (ACF) interconnects between flexible printed circuits (FPC) and glass substrates prepared under a variety of bonding conditions. The curing behavior of the ACF was analyzed by the time-temperature-superposition (TTS) method. TTS analysis using the superposition principle has been suggested as a suitable technique for analyzing the curing kinetics during the bonding process, although an appropriate shift factor needs to be established. However, the glass transition temperature of the cured ACF and the peel strength of the ACF joints cannot be determined uniquely from the degree of conversion. Therefore, the polymer structure of the adhesive binder obtained by the bonding process is inferred as being different depending on the bonding temperature, even for the same degree of conversion. The quality of the electrical connection of the joints after the bonding process is rarely affected by differences in the polymer structure.