Elimination of dielectric degradation for chemical-mechanical planarization of low-k hydrogen silisesquioxane

Abstract

The characteristics of post-chemical mechanical polishing (post-CMP) low-k hydrogen silsesquioxane (HSQ) have been investigated in this work. Dielectric properties of HSQ are damaged by the CMP process. We propose NH3-plasma treatment to improve the characteristics of post-CMP HSQ film. Both of the leakage current and dielectric constant of NH3 plasma-treated HSQ are significantly decreased as compared with those of untreated HSQ. NH3 plasma treatment slightly nitridates the surfaces of the polished HSQ film. The thin nitride layer prevents moisture absorption in the post-CMP HSQ. As a result, the dielectric degradation of HSQ after the CMP process can be effectively recovered using the NH3 plasma treatment.