A study on the Anchoring Polymer Layer (APL) Anisotropic Conductive Films (ACFs) with self-exposed conductive particles surface for ultra-fine pitch Chip-on-Glass (COG) applications

Abstract

In this study, APL ACFs combined with self-exposed conductive particles surface are newly introduced. The effects of APL ACFs properties on conductive particle movement and interconnection stability for ultra-fine pitch COG applications were reported earlier, Due to the APL structure with high tensile strength, the movement of conductive particles can he suppressed when the resin flow occurs, thereby achieving 100 % of electrical insulation property in ultra-fine pitch COG interconnection. Due to the high tensile strength property of the thermoplastic polymer as an APL material, APL ACFs have a higher capture rate than conventional ACTS, which can reduce the amount of conductive particles used to make ACTS by one third. However, to achieve a stable electrical interconnection, the APL ACTS require additional process steps such as an oxygen plasma etching process to remove the APL polymer skins coated on the top and bottom surfaces of conductive particles. In this study, the polymer skin can be removed during the APL fabrication process using the self-activate monolayer (SAM) treatment on conductive particles. As a result, stable ACFs joint formation can be achieved without any additional oxygen plasma etching process for APL fabrication processes.