High Performance Anisotropic Conductive Adhesives Using Copper Particles With an Anti-Oxidant Coating Layer

This paper describes the development and characterization of anisotropically conductive films (ACFs) incorporated with copper (Cu) particles as electrically conductive fillers for environmentally friendly, low cost, high electrical, and high thermal interconnect applications in microelectronics packaging. The Cu particle surface modification by a coupling agent and its effects on the electrical conductivity and thermal stability of Cu-filled ACF joints were investigated for the potential alternatives of conventional Au-coated polymer and Au-coated Ni-filled ACFs. The surface characteristics of a thin film of the coupling agent on copper surfaces such as element analysis, their hydrophobicity, and thermal stability were evaluated. The treated Cu ball-filled ACF showed the lowest contact resistance $1.0×10−5Ω$⁠, higher current carrying capability, and higher thermal stability of ACF joints compared with the conventional Au-coated polymer ball and Au-coated Ni ball-filled anisotropically conductive adhesives.