Kinetically controlled assembly of terpheny-4,4”-dithiol self-assembled monolayers (SAMs) for highly conductive anisotropically conductive adhesives (ACA)

Anisotropically conductive adhesives (ACA) are a promising alternative to solder interconnects for high performance electronic devices due to their increased I/O capabilities and reduced form factor. Previous studies have shown that modification of Au coated Ni/Cu bumps with conjugated self-assembly monolayers (SAMs) increases conductivity, current carrying capacity and reliability of ACA interconnects[1-3]. In this study, we kinetically control the assembly of p-Terphenyl-4,4”-dithiol (TPD) monolayers on Au bumps. Using a custom designed test vehicle we show how TPD SAMs can either increase or decrease the single bump resistance depending on the kinetics of the monolayer formation and its resulting structure. Future studies focusing on controlling monolayer assembly will determine the efficacy of conjugated SAMs at enhancing the conductivity and current carrying capacity of ACA interconnects.