A study on the novel anchoring polymer layer(APL) anisotropic conductive films(ACFs) for ultra fine pitch assembly applications

Abstract

In this study, novel thermoplastic APL structure has been newly introduced into the conventional ACFs system. The APL structure can effectively suppress the movement of conductive particles during the ACFs bonding process resulting in significant improvement of conductive particle capture rate on a bump and solving electrical short problems at ultra-fine pitch assemblies such as COG(Chip On Glass) and COF(Chip On Flex) applications. The selection of thermoplastic material of APL structure determine the efficiency of suppressing conductive particles movement. The Nylon, one of the strongest mechanical properties thermoplastic materials among various thermoplastic materials, has been introduced. And the effects of Nylon APL ACFs properties on conductive particle movement and interconnection stability of ultra-fine pitch COG applications were investigated. After the 20 μm pitch COG assembly using APL ACFs, the conductive particles capture rate of the Nylon APL ACFs shows 90% compared with 33% of conventional ACFs. In addition, the Nylon APL ACFs showed no short circuit problem at the 20 μm pitch COG assembly.