High Performance Nonconductive Film with π-Conjugated Self-Assembled Molecular Wires for Fine Pitch Interconnect Applications

Abstract

In this paper, we introduce a novel approach of using π-conjugated molecular wires to improve the electrical properties of nonconductive films (NCFs) for the electronic interconnects. Two thiol (-SH) terminated conjugated molecular wires, 1,4-benezenedithiol (BDT) and biphenyldithiol (BPD), are incorporated into an NCF formulation and investigated. The molecular wires can be well assembled on the gold (Au) electrodes and improve the interfacial properties of the NCF joints. The BPD exhibits higher thermal stability after curing at 150°C than BDT due to the higher aromaticity (more aromatic rings) and thus more rigid structure. Formation of a self-assembled monolayer on Au electrodes can tune the effective work function (Φ) of Au electrodes and reduce the tunnel resistivity. Therefore, the joint resistance of NCF joints, which is the sum of tunnel resistance and constriction resistance, can be significantly reduced from 0.15 × 10−3 Ω to 0.1 × 10−3 Ω and 0.05 × 10−3 Ω with BDT and BPD, respectively. The improved electrical conduction and current carrying capability enables the application of the NCF in fine pitch and high performance electronic interconnects in microelectronics.