Barrier-metal-free (BMF), Cu dual-damascene interconnects with Cu-epi-contacts buried in anti-diffusive, low-k organic film

摘要

Barrier-metal-free (BMF), Cu dual-damascene interconnects (DDI) are fabricated in the plasma-polymerized, divinyl siloxane bis-benzocyclobutene (p-BCB: k=2.6) polymer film, which is featured by the anti-diffusive characteristics for the Cu. The BMF-structure has inter-line leak current as low as that of a conventional barrier-inserted structure and is estimated to keep the high insulating property over 10 years under 1MV/cm. The BMF-structure also derives Cu-epi-contacts, reducing the via-resistance of 50% to the conventional Cu/barrier/Cu contacts. The effective dielectric constant was k{sub}(eff)=3.l including very thin SiN etch-stop-layers, accomplishing 20%-fast CMOS device operation to that of the conventional Cu-DDI in the SiO{sub}2 with Ta/TaN harriers. The BMF, Cu-DDIs buried directly in the p-BCB film is one of the ultimate structures for high performance, 0.1 μm-CMOS devices and beyond.