Novel sidewall capping for degradation-free damascene trenches of low-permittivity methylsilsesquioxane

Abstract

A low-permittivity organic dielectric, methylsilsesquioxane (MSQ), used as an interlevel dielectric is expected to reduce the parasitic capacitance in integrated circuit. However, MSQ film can he easily degraded during resist ashing after the film is etched with the damascene trenches being created. In this work, a novel sidewall capping technology is developed to solve the degradation issue. Prior to resist ashing, a high-quality, low-permittivity oxide him is selectively deposited onto the sidewalls of MSQ trenches using selective liquid-phase deposition. Experimental results demonstrate that the capping oxide can effectively protect the sidewalls of MSQ trenches from ashing-induced degradation.