O-2-plasma degradation of low-k organic dielectric and its effective solution for damascene trenches

Abstract

Methylsilsesquioxane, an organic spin-on dielectric, has attracted much attention as a promising low-k inter-Cu-metal dielectric because of its sufficiently low dielectric constant (<2.8) and excellent thermal stability (>500 degreesC). However, we found that MSQ film would be easily degraded during resist ashing in O-2-plasma ambient after the film is etched with the damascene trenches being created. An innovative sidewall capping technology as an effective solution of this ashing-induced degradation has been successfully developed. This new technology has potential to fulfill the highly reliable damascene process toward Cu/MSQ integration.