Manufacturing advancements in an organic SOG process by Ar+ implantation

Organic spin-on glass (SOG) is widely utilized as an inter-layer dielectric (ILD) in the fabrication of multilevel interconnections because of its excellent gap fill and planarization properties. Unfortunately, its relatively low material cost is offset by the need to etch-back SOG whenever it is left on top of metal lines to avoid “via poisoning”. This etch-back process nor only increases complexity and cost, but reduces yield. A modified SOG process utilizing Ar⁺ implantation to densify SOG, so it can be used as a non etch-back film, has been integrated into a four metal level 0.5 μm CMOS process. This paper will present data outlining the chemical and physical properties of Ar⁺ implanted SOG films and show that an implanted SOG process produces equivalent or better electrical and probe results when compared to an etch-back SOG process